Hierarchical Analysis of Self-Assembled PEGylated Hexaphenylalanine Photoluminescent Nanostructures

Chemistry. 2016 Nov 7;22(46):16586-16597. doi: 10.1002/chem.201604107. Epub 2016 Oct 5.

Abstract

Despite the growing literature about diphenylalanine-based peptide materials, it still remains a challenge to delineate the theoretical insight into peptide nanostructure formation and the structural features that could permit materials with enhanced properties to be engineered. Herein, we report the synthesis of a novel peptide building block composed of six phenylalanine residues and eight PEG units, PEG8 -F6. This aromatic peptide self-assembles in water in stable and well-ordered nanostructures with optoelectronic properties. A variety of techniques, such as fluorescence, FTIR, CD, DLS, SEM, SAXS, and WAXS allowed us to correlate the photoluminescence properties of the self-assembled nanostructures with the structural organization of the peptide building block at the micro- and nanoscale. Finally, a model of hexaphenylalanine in aqueous solution by molecular dynamics simulations is presented to suggest structural and energetic factors controlling the formation of nanostructures.

Keywords: diphenylalanine; molecular dynamics; nanostructures; peptide materials; photoluminescence.