Conductive polymeric composites of polycaprolactone fumarate and polypyrrole for nerve regeneration

摘要

A novel electrically conductive polymer composite composed of polycaprolactone fumarate-polypyrrole (PCLF-PPy) for applications in nerve regeneration is disclosed. The synthesis and characterization of PCLF-PPy and in vitro studies showing PCLF-PPy supports both PC12 cell and Dorsal Root Ganglia neurite extension. PCLF-PPy composite materials were synthesized by polymerizing pyrrole in pre-formed scaffolds of PCLF resulting in an interpenetrating network of PCLF-PPy. PCLF-PPy composite materials possess electrical conductivity up to 6 mS cm-1 with compositions ranging from 5-13.5 percent polypyrrole of the bulk material. Surface topographies of PCLF-PPy materials show microstructures with a RMS roughness of 1195 nm and nanostructures with RMS roughness of 8 nm. PCLF-PPy derivatives were synthesized with anionic dopants to determine effects on electrical conductivity and to optimize the chemical composition for biocompatibility. In vitro studies using PC12 show PCLF-PPy composite materials induce a higher cellular viability and increased neurite extension compared to PCLF. PCLF-PPy composites doped with either naphthalene sulfonic acid or dodecyl benzene sulfonic acid are determined to be the optimal materials for electrical stimulation. In vitro studies showed significant increases in percentage of neurite bearing cells, number of neurites per cell and neurite length in the presence of ES compared to no ES. Additionally, extending neurites were observed to align in the direction of the applied current. Electrically conductive PCLF-PPy scaffolds possess material properties necessary for application as nerve conduits. Additionally, the capability to significantly enhance and direct neurite extension by passing electrical current through PCLF-PPy scaffolds renders them even more promising as future therapeutic treatments for severe nerve injuries.