Development of Electrically Conductive Oligo(polyethylene glycol) Fumarate-Polypyrrole Hydrogels for Nerve Regeneration

Electrically conductive hydrogel composites consisting of oligo(polyethylene glycol) fumarate (OFF) and polypyrrole (PPy) were developed for applications in nerve regeneration. OFF-PPy scaffolds were synthesized using, three different anions: naphthalene-2-sulfonic acid sodium salt (NSA), dodecylbenzenesulfonic acid sodium salt (DBSA), and dioctyl sulfosuccinate sodium salt (DOSS). Scaffolds were characterized by ATR-FTIR, XPS, AFM, dynamic mechanical analysis, electrical resistivity measurements, and swelling experiments. OPF-PPy scaffolds were shown to consist of up to 25 mol % polypyrrole with a compressive modulus ranging from 265 to 323 kPa and a sheet resistance ranging from 6 to 30 x 10(3) Ohms/square. In vitro studies using PC 12 cells showed OPF-PPy materials had no cytotoxicity and PC 12 cells showed distinctly better cell attachment and an increase in the percent of neurite bearing cells on OFF-PPy materials compared to OFF. The neurite lengths of PC 12 cells were significantly higher on OPF-PPyNsA and OPF-PPyDBSA. These results show that electrically conductive OPF-PPy hydrogels are promising candidates for future applications in nerve regeneration.