bm4005645_si_001.pdf (571.37 kB)
The Robust Hydrogel Hierarchically Assembled from a pH Sensitive Peptide Amphiphile Based on Silk Fibroin
journal contribution
posted on 2013-08-12, 00:00 authored by Hui Guo, Jinming Zhang, Tao Xu, Zhidong Zhang, Jinrong Yao, Zhengzhong ShaoSupramolecular polymers can be formed
by self-assembly of designed
subunits to yield highly ordered materials. In this paper, hierarchically
structured materials, from molecules to nanofibers to macroscopical
hydrogel, were fabricated by pH-induced assembly of C12-GAGAGAGY, a peptide amphiphile (PA) based on silk fibroin. Due to
the different acid dissociation constants of the carboxyl and phenolic
hydroxyl groups on tyrosine residue (Y), the PAs showed unique pH
sensitive assembly and aggregation behaviors. It was found that not
only the molecular-scale assemblies of these PAs gradually changed
from cylindrical nanofibers to nanoribbons with the decreasing of
pH value from 11 to 8 but also most of nanoribbons aggregated into
parallel bundles in such a case. Further decrease of pH value resulted
in a hierarchically structured robust and plastic hydrogel, of which
the rheological moduli reached around 105 Pa. Moreover,
noodle-like hydrogel fibers with bundles of nanoribbons aggregated
parallel along the long axis in them could be steadily prepared under
shear force. Taking the pH-sensitive reversible sol–gel transition,
high modulus and plasticity into account, the hydrogel is believed
to have significant potential applications in tissue engineering or
as the biocompatible adhesives.