# Zn(II)-Responsive Peptide Hydrogels with Tunable Mechanical Properties

## TL;DR

This paper describes the creation of hydrogels using zinc-responsive peptides, which can be tuned for mechanical properties and have potential in biomaterials and 3D printing.

## Contribution

The study introduces Zn(II)-driven hydrogelation of short amphiphilic peptides with tunable mechanical and functional properties.

## Key findings

- Zn(II) coordination enhances the mechanical robustness of the hydrogels.
- The hydrogels exhibit thixotropic behavior, making them suitable for injectable and 3D printing applications.
- The hydrogels show moderate antibacterial activity against E. coli and S. aureus.

## Abstract

Metal-coordinated
peptide assemblies represent a versatile
platform
for functional biomaterials; here we describe Zn­(II)-driven hydrogelation
of short amphiphilic peptides. To this end, we synthesized two short
amphiphilic hexapeptides, Ac-LIVKHH-NH2 and Fmoc-LIVKHH-NH2, using standard Fmoc/Boc solid-phase peptide synthesis. Upon
interaction with Zn­(II) salts in aqueous solution (pH 7), these peptides
encapsulate large volumes of water to form metallo-hydrogels. The
Zn­(II)-mediated gelation and structural organization of the resulting
supramolecular architectures were examined using circular dichroism
(CD), Fourier transform infrared spectroscopy (FTIR), transmission
electron microscopy (TEM) and scanning electron microscopy (SEM),
respectively. Oscillatory rheology and thixotropy measurements confirmed
the viscoelastic and shear-recoverable properties of the hydrogels.
Zn­(II) coordination was found to play a key role in enhancing mechanical
robustness, while the thixotropic behavior highlights their potential
as injectable carriers and bioinks for 3D printing. Antibacterial
assays against Escherichia coli and Staphylococcus aureus further revealed moderate inhibition
zones, indicating additional functional utility. Overall, this work
provides new insights into the Zn­(II)-responsive assembly of short
amphiphilic peptides and establishes a foundation for their development
in biomaterials and materials science.