(203e) Stiffness Tunable Peptide Amphiphile Hydrogels As Three Dimensional Cell Scaffolds

Peptide amphiphiles (PA) are an emerging class of materials that have
been sought after for a wide breadth of applications including tissue
engineering, drug delivery, vaccine, and biocatalysis. The bulk
properties and modularity of PA-based hydrogels have made them
particularly successful as cell scaffolds. The surface functionality
of the gels can be easily modified by incorporating different PAs.
However, little effort has been directed towards the tunability of gel
stiffness, which has been demonstrated as an important cue in
applications such as stem cell differentiation or regenerative
medicine. In this report, we present our recent design of a pH
responsive PA hydrogel as a three dimensional cell scaffold. The
hydrogels exhibit pH responsiveness in the physiological range, where
the stiffness is modulated by controlling peptide sidechain
interactions. Below pH 6 the PAs are weak gels or viscous solutions
and above pH 7, they form gels with storage moduli that range from 100
to 10,000 Pa.  The applicability of this material as a three
dimensional scaffold was examined with 3T3 fibroblasts, where cell
toxicity was not observed over 72 hours. The design, physiochemical
properties, and applications of this PA hydrogel will be discussed.