(489h) Peptide Amphiphile Hydrogels As 3D Scaffolds for Tissue Engineering

Peptide amphiphiles are an attractive scaffold material for tissue engineering applications due to their biocompatibility and ability to self-assemble into nanofibers. The Kokkoli group has previously developed a fibronectin-mimetic peptide amphiphile, PR_g, which self-assembles into nanofibers in aqueous environments and forms hydrogels.The PR_g peptide, which specifically binds the α₅β₁ integrin, contains both the RGDSP cell binding site and the PHSRN synergy site separated by a spacer that mimics the separation length as well as the hydrophobicity/hydrophilicity in the native structure of fibronectin. As surfaces, PR_g hydrogels have been shown to support improved cell adhesion, proliferation and extracellular matrix (ECM) production compared to mechanically matched PEG hydrogel surfaces functionalized with full length fibronectin. However, traditional two dimensional (2D) culture is often insufficient to mimic the natural, three dimensional (3D) environment of a cell. Cells have been shown to proliferate and migrate faster in 3D culture and there is evidence that integrin and receptor expression varies between 2D and 3D culture environments. We hypothesize that the incorporation of PR_g into a 3D scaffold will support improved cell viability and proliferation. As such, this work develops gelation protocols for 3D cell entrapment using the PR_g peptide amphiphile and a diluent peptide amphiphile.  Additionally, this work evaluates the effects of gel stiffness and PR_g ligand concentration on cell viability, proliferation and ECM production in a 3D environment.