Long-term biocompatibility of implanted polymer-based intrafascicular electrodes.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Materials Science

Background:

• Chronic implantation of neural interfaces is crucial for long-term neuroprosthetics.
• Assessing the biocompatibility and long-term effects of implantable electrodes is essential.
• Polymer-based longitudinal intrafascicular electrodes (polyLIFEs) offer potential for nerve regeneration and interfacing.

Purpose of the Study:

• To evaluate the long-term biocompatibility of polyLIFEs implanted in rabbit sciatic nerves for 6 months.
• To assess the impact of polyLIFEs on nerve fiber morphology and structure.
• To investigate the tissue response surrounding the implanted electrodes.

Main Methods:

• Chronic implantation of polyLIFEs into the sciatic nerve of rabbits (n=8) for 6 months.
• Sham-treated control group (n=9) to control for surgical procedure effects.
• Histological analysis of nerve fiber counts, diameter, and myelin thickness at multiple sites.

Main Results:

• No significant differences in nerve fiber counts, fiber diameters, or myelin thickness were observed between polyLIFEs and control groups.
• A thin, dense connective tissue capsule formed around the implanted polyLIFEs.
• Minimal inflammatory or degenerative changes were noted in the nerve tissue.

Conclusions:

• PolyLIFEs demonstrate excellent long-term biocompatibility when implanted in the sciatic nerve.
• The formation of a thin capsule suggests a localized and non-disruptive tissue response.
• PolyLIFEs are a promising candidate for chronic neural interfacing applications.