Carbon nanofibers:polycarbonate urethane composites as a neural biomaterial

Chronic neural implants are usually made from silicon materials and are subject to scar tissue formation at the tissue/implant interface, which interferes with their functionality. Carbon nanofibers are an example of a material that may improve neural implant interactions with native cell populations since these nanofibers have promising cytocompatibility, mechanical, and electrical properties. Neural implants may achieve better tissue interactions simply by incorporating carbon nanofibers into a polymer matrix. Polycarbonate urethane and carbon nanofiber composites have induced neurite extension during in vitro studies. The objective of the present study was to use an electrical field to align carbon nanofibers in a polycarbonate urethane matrix. Polycarbonate urethane was dissolved in chloroform, and then mixed with carbon nanofibers of high and low surface energies separately. When the solution was viscous, it was pored into a parallel copper plate capacitor chamber. Alignment occurred after exposure to 500 to 700 volts. The aligned nanofiber structure was maintained after the polymer cured. These materials have been prepared to determine if neuron axonal extension will be affected by the carbon nanofiber alignment. These materials have promising tunable properties for neural implants such as electrical, nanoscale structure and organization, and surface energy characteristics.