Smart Sutures That Detect Infections

Plastic or silk threads covered with temperature sensors and micro-heaters could keep tabs on infections and provide therapy.

Surgical sutures are mindless threads no more. Researchers have now coated them with sensors that could monitor wounds and speed up healing.

The electronic sutures, which contain ultrathin silicon sensors integrated on polymer or silk strips, can be threaded through needles, and in animal tests researchers were able to lace them through skin, pull them tight, and knot them without degrading the devices.

The sutures can precisely measure temperature—elevated temperatures indicate infection—and deliver heat to a wound site, which is known to aid healing. And John Rogers, professor of materials science and engineering at the University of Illinois at Urbana-Champaign and inventor of the smart sutures, imagines that they could also be laden with devices that provide electrical stimulation to heal wounds. “Ultimately, the most value would be when you can release drugs from them in a programmed way,” he says. The researchers could do that by coating the electronic threads with drug-infused polymers, which would release the chemicals when triggered by heat or an electrical pulse.

The smart sutures, reported online in the journal Small, rely on silicon-based devices that flex and stretch. Rogers and his colleagues make the devices with silicon membranes and gold electrodes and wires that are just a few hundred nanometers thick and patterned in a serpentine shape. The technology, which they have also used ininflatable catheters and medical tattoos (see “Stick-On Electronic Tattoos“), is beingcommercialized by MC10, a Cambridge, Massachusetts–based startup Rogers cofounded (see “Making Stretchable Electronics“).