A balloon catheter features stretchable circuits configured into open-mesh designs that consist of springy wire interconnects bonded to an underlying rubber sheet.

Many medical device applications are relying increasingly on complex electronics to perform an array of functions, such as sensing, ablating, monitoring, and analyzing. But as long as electronics are fabricated on inflexible semiconductor substrates, they will be ill suited for accommodating curvilinear device surfaces. Addressing this limitation, John Rogers and his team of scientists at the University of Illinois at Urbana-Champaign (U of I) have developed flexible, stretchable electronics that are now being incorporated into balloon catheters for performing an assortment of diagnostic and surgical functions.

Conventional electronics are built on rigid, planar semiconductor wafers, according to Rogers, the Lee J. Flory-Founder chair in engineering at U of I. “What we were interested in is building circuits with the kinds of performance capabilities associated with state-of-the-art silicon-type devices, but in formats that can be bent, stretched, folded, and even manipulated like a rubber band or a balloon.”

Flexible electronics can be achieved relatively easily by using a sheet of silicon that is perhaps a thousand or ten thousand times thinner than a silicon wafer, Rogers explains. But going beyond flexibility, the U of I team has achieved stretchable electronics by configuring circuits into open-mesh designs consisting of springy wire interconnects bonded to an underlying rubber sheet. “We’ve exploited these two ideas—thinness and mesh geometry—to integrate a range of sensor and electronic functionalities onto the surface of an otherwise conventional balloon catheter,” Rogers says.