The stability of implanted electrodes is a significant problem affecting their long-term use in vivo. Problems include mechanical failure and inflammation at the implantation site. The engineering of bioactive electrode coatings has been investigated for its potential to promote in-growth of neural tissue and reduce sheer at the electrode-host interface. Preliminary results indicate that hydrogel coatings with either collagen I or polylysine-laminin-1 can promote cortical nerve cell attachment and differentiation on silicon substrates. Additionally, slow-release microtubules can also be implanted in these gels to release agents that either provide trophic support to neurons or prevent inflammation locally. When silicon discs are coated with collagen type I, the coating remains stable for 55 days. Further testing is underway, but initial results indicate that tissue-engineering approaches provide useful insights to help address the problem of host-electrode instability in the brain.
J. Rehabil. Res. Dev.38, 627–32 (2001).