Most electronics are made in the form of integrated circuits, which are tiny chips that contain transistors and other components etched onto silicon wafers. While fine for computers and other products, they are inflexible and cannot be easily wrapped around curved surfaces or pliable ones, making them hard to be used in the body. Researchers have devised ways to make flexible electronics, for such things as electronic paper. Now, John Rogers of the University of Illinois, Urbana-Champaign, who is one of the pioneers of flexible electronics, has devised a new technique to create ultra-thin and flexible circuits suitable for medical use.
Dr Rogers first fabricated a mesh containing a circuit of silicon electronics by thinning silicon until it becomes flexible. But this causes a problem. Since it is so thin, it soon collapses. To avoid this, Dr Rogers deposited the circuit onto a special silk to provide structural support without sacrificing flexibility. The silk was engineered by Tufts University, near Boston, from a silkworm cocoon that had been boiled to create a silk solution that can be deposited as a thin film. When the film containing the circuit is placed on biological tissue, it dissolves naturally. What it leaves behind is the circuit, attached to the tissue by capillary forces and supported by it.