A team of cardiologists, materials scientists, and bioengineers have created and tested a new type of implantable device that, among other options, can measure the heart’s electrical output in a way that improves on current devices. The new device uses flexible silicon technology to apply electronic circuits directly to tissue.

“We believe that this technology may herald a new generation of active, flexible, implantable devices for applications in many areas of the body,” says cosenior author Brian Litt, MD, an associate professor of neurology at the University of Pennsylvania School of Medicine and also an associate professor of bioengineering in the school of engineering and applied science. “Initially, we plan to apply our findings to the design of devices for localizing and treating abnormal heart rhythms.” Litt believes these devices allow doctors to quickly, safely, and accurately target and destroy abnormal areas of the heart.

“The new devices bring electronic circuits right to the tissue, rather than having them located remotely, inside a sealed can that is placed elsewhere in the body, such as under the collarbone or in the abdomen,” explains Litt. “This enables the devices to process signals right at the tissues, which allows them to have a much higher number of electrodes for sensing or stimulation than is currently possible in medical devices.”

Current technologies for mapping and eliminating life-threatening heart rhythms allow for up to 10 wires in a catheter that is moved in and around the heart and is connected to rigid silicon circuits distant from the target tissue. Such design limits the complexity and resolution of devices because the electronics cannot get wet or touch the target tissue.

In contrast, the circuit device is made of nanoscale, flexible ribbons of silicon embedded with 288 electrodes, forming a latticelike array of hundreds of connections and 2000 transistors. The shape hugs the tissue, enabling measurements of electrical activity with greater resolution in time and space. The device can operate even when exposed to the body’s fluids. It collects large amounts of data at a high speed.

Researchers tested the device on porcine hearts. The proof-of-principle findings were published in a recent issue of Science Translational Medicine. “Our hope is to use this technology for many other kinds of medical applications, for example to treat brain diseases like epilepsy and movement disorders,” says Litt.

The team plans to design advanced pacemakers that can improve the pumping function of hearts weakened by heart attacks and other diseases. For each of these applications, researchers are conducting experiments to test flexible devices in animals before starting human trials.

Another focus of the work is to develop similar types of devices that are not only flexible, like a sheet of plastic, but fully stretchable. A device that can fully conform and wrap around large areas of curved tissues could be the next big step. Moving to the next generation will require attaching a power source.

This research is a result of a collaboration between the Rogers laboratory, where the flexible electronics technology in the devices was developed and fabricated, and Litt’s bioengineering laboratory at the University of Pennsylvania. The research was funded by the National Institute of Neurological Disorders and Stroke, the Klingenstein Foundation, the Epilepsy Therapy Project, and the University of Pennsylvania Schools of Engineering and Medicine.