Making Stretchable Electronics

MC10, a startup in Cambridge, Massachusetts, is getting ready to commercialize high-­performance electronics that can stretch. The technology could lead to such products as skin patches that monitor whether the wearer is sufficiently hydrated, or inflatable balloon catheters equipped with sensors that measure electrical misfiring caused by cardiac arrhythmias. 

Microelectronics have long “depended on a rigid, brittle wafer,” says David Icke, MC10’s CEO. MC10 uses a few tricks to change that. To make both the hydration-­sensing patch and the catheter, gold electrodes and wires just a few hundred nanometers thick are deposited on silicon wafers by conventional means, then peeled off and applied to stretchable polymers. The serpentine wires elongate when the polymers stretch, either when the balloon inflates in the heart or as the patch moves around on the skin. The electrodes measure electrical impedance to detect the electrical signals in cardiac tissue or moisture levels in the skin.

The company is building on lab prototypes made by University of Illinois materials scientist John Rogers, a company cofounder. Rogers’s technologies have advantages over other approaches to flexible electronics. For example, organic polymer electronics can only bend, not stretch, and they are slower than devices made of inorganic semiconductor materials or precious metals such as gold, so they can’t provide precise real-time biological readings.

MC10’s first product, expected to launch in late fall, will be a wearable device developed in a partnership with Reebok. The company is tight-lipped about the details. But in addition to its hydration patch, it is working on patches that use sensors to detect heartbeat, respiration, motion, temperature, blood oxygenation, and combinations of these indicators.

MC10’s skin patches can wirelessly transmit information to a nearby smartphone. A phone with a near-field communication chip can be waved over the patch, or the patch can be paired with a thin-film battery made by a commercial supplier, allowing continuous data transmission.

Next up will be balloon catheters that a cardiologist could snake through the heart to detect areas of misfiring cardiac tissue. Some of the prototypes in preclinical testing have dense arrays of electrodes that allow high-resolution mapping and ablation of that tissue. Further off are other medical devices, including implantable materials that conform to brain tissue, sensing seizures and stopping them.