Polylysine-modified PEG-based hydrogels to enhance the neuro-electrode interface.

Neural prostheses are a promising technology in the treatment of lost neural function. However, poor biocompatibility of these devices inhibits the formation of a robust neuro-electrode interface. Several factors including mechanical mismatch between the device and tissue, inflammation at the implantation site, and possible electrical damage contribute to this response. Many researchers are investigating polymeric brain mimetic coatings as a means to improve integration with nervous tissue. Specifically, hydrogels, constructs also employed in tissue engineering, have been explored because of their structural and mechanical similarity to native tissue. However, many hydrogel materials (e.g., poly(ethylene glycol) (PEG)) do not support cell adhesion. In this work, we report a technique to enhance the interface between polymeric brain mimetic coatings and neural tissue using adhesion molecules. In particular, polylysine-modified PEG-based hydrogels were synthesized, characterized and shown to promote neural adhesion using a PC12 cell line. In addition, we examined adhesion behavior of a PEG-co-polymer and found that these materials adhere to electrodes for at least 4 weeks. These results suggest that polylysine-PEG hydrogel biomaterials are biocompatible and can enhance stability of chronic neural interfaces.