Mechanically adaptive nanocomposites as basis for biomedical implants

In collaboration with several partners we study if mechanically adaptive polymer nanocomposites can solve a key problem of cortical interfaces.

Cortical microelectrodes can provide intimate contacts with neural cells and show promise as electrical interfaces to the brain, which permit the treatment of a range of neurological deficits. The functionality of current electrodes, however, decreases over time, which is to a significant extent caused by neuron degeneration and foreign body encapsulation. One hypothesis is that the mismatch of the mechanical properties of the electrode and the brain tissue is a significant contributor to these events. In collaboration with the groups of Profs. Jeff Capadona, Stuart Rowan, Dustin Tyler, and Chris Zorman (all at Case Western Reserve University) we are studying whether this problem can be alleviated through the use of physiologically-responsive, mechanically adaptive polymer nanocomposites. These bio-inspired materials are initially rigid, but soften considerably upon exposure to physiological conditions. Initial histological evaluations suggest that neural prosthetics based on such mechanically adaptive materials can more rapidly stabilize neural cell populations around the implant than rigid reference systems. Pronounced reductions in the populations of reactive microglia and astrocytes were observed at the implant-tissue interface for the compliant materials.  The compliant materials also offered a better stability of the blood-brain barrier than the rigid materials with the same surface chemistry.

Adolphe Merkle Institute - Chemin des Verdiers 4 - CH-1700 Fribourg - Phone +41 26 300 9254