Chiral Glass Formation by Dipeptide Salts

TL;DR

A dipeptide salt forms a chiral glass with moldable, transparent, and self-healing properties, offering potential for various applications.

Contribution

The discovery of chiral glass formation from dipeptide salts via a simple evaporation method.

Findings

Dipeptide WR salts form glasses with moldability, transparency, and fluorescence.

The glasses exhibit self-healing, adhesion, and accessible glass transition temperatures.

Chirality in the glasses is confirmed by circular dichroism spectroscopy.

Abstract

A simple dipeptide WR (tryptophan–arginine) in
the form
of salts with organic acids tartaric acid or crotonic acid is shown
to form glasses through a benign preparation route by evaporation
of aqueous solution. The glasses have a remarkable range of properties
including moldability, high transparency across a broad range of wavelengths,
and fluorescence. The glasses show self-healing and adhesive properties,
and have accessible glass transition temperatures. The glasses are
shown to be amorphous via small-angle and wide-angle X-ray scattering
(SAXS/WAXS) and scanning electron microscopy (SEM). Remarkably, the
glasses are found to have a chiral structure, as shown by circular
dichroism (CD) spectroscopy. Investigation of glass precursor dipeptide
salt solutions shows that the glasses form from an initial unordered
solution containing chiral peptide molecules. The diverse properties
of the dipeptide glass materials points to a wide range of potential
future applications.

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