Smart sutures detect infection, promote healing

A university researcher has developed a smart suture that detects and responds to signs of infection, helping wounds heal more quickly.

As described in this month's issue of the scientific journal Small, the suture incorporates actuators, sensors and semiconductor devices onto thin strips of plastics or biopolymers to monitor and accelerate healing. Live-animal testing has shown promise, according to the article, and modeling suggests the sutures can hold up to real-world functionality in humans.

Specifically, the animal tests showed the sutures could be laced through skin and pulled tight without degrading the electronics, reported MIT's Technology Review.

According to that article, the sutures monitor tissue temperature and deliver heat to aid healing if rising temperatures indicate infection is developing. Eventually, the hope is that the electronics also could heal wounds through electronic stimulation and the programmed release of healing drugs, inventor John Rogers of the University of Illinois at Urbana-Champaign told Technology Review.

Here's how the article describes the making of the sutures: Ultrathin strips of silicon are sliced from a wafer using chemicals, with the nanomembranes then transferred via rubber stamp to polymer or silk strips. Metal electrodes or wires are laid on top, with the entire device then coated in epoxy.

The temperature sensors are a silicon diode and a platinum nanomembrane resistor. Gold-filament micro-heaters warm when an electrical current passes through them, according to Technology Review.

Smart sutures are just the latest of a series of futuristic IT-enabled medical devices being developed in laboratories around the world.

A smart cast called "Bones," for example, is laced with electromyographic (EMG) sensors that track muscle activity as a fracture heals and relays that data to clinicians. The cast has software that can suggest exercises to promote better healing, and project how long it will take for the fracture repair to be complete.

Researchers in Pennsylvania, meanwhile, have developed an ultra thin sensor that adheres to skin for remote patient monitoring. The sensors provided a signal comparable with those of standard electrodes attached with gel and taped in place, the researchers said.

And researchers at Northeastern University in Boston have developed nanosensors that, when injected just under the skin, glow under a special LED light based on glucose levels. They also developed an iPhone attachment with the three-way LED lighting, takes an image of the resulting fluorescence and relays that to medical providers.

To learn more:
- check out the Small article (subscription required)
- read the Technology Review story