The biocompatible circuits the first ones unperturbed by immersion in the body's salty fluids represent a culmination of seven years of flexible electronics study by Rogers' group. The researchers build circuits from ultrathin, single-crystal silicon on a flexible or stretchy substrate, like a sheet of plastic or rubber. The nanometer thinness of the silicon layer makes it possible to bend and fold the normally rigid semiconductor.
"If you can create a circuit that's compliant and bendable, you can integrate it very effectively with soft surfaces in the body," such as the irregular, constantly moving curves of the heart, Rogers said.
Collaborations with a theoretical mechanics group at Northwestern University, led by Younggang Huang, yielded important insights into the designs.
The patchwork grid of cardiac sensors adheres to the moist surfaces of the heart on its own, with no need for probes or adhesives, and lifts off easily. The array of hundreds of sensors gives cardiac surgeons a more complete picture of the heart's electrical activity so they can quickly find and fix any short circuits. In fact, the cardiac device boasts the highest transistor resolution of any class of flexible electronics for non-display applications.
The team's next step is to adapt the technology for use with non-invasive catheter procedures, Rogers said. The U. of I. and Pennsylvania teams also are exploring applications for the arrays in neuroscience, applying grids to brain surfaces to study conditions of unusual electrical activity, such as epilepsy.
"It sets out a new design
|Contact: Liz Ahlberg|
University of Illinois at Urbana-Champaign