Wearable, implantable ‘soft robots’ could someday make our bodies stronger

Heart failure — when the heart is too weak to pump enough blood through the body — affects nearly 6 million American adults. But recent innovations in muscle-like “soft robots” may someday provide a respite for heart failure patients, and patients suffering from a host of other muscular ailments.

Soft robots “are very different from conventional robots with rigid parts, but they're robotic in the sense that you can program them to achieve a predefined motion,” says Ellen Roche, a postdoctoral researcher at the National University of Ireland.

Roche and her team have designed a robotic silicone sleeve that fits around the heart. She explains it’s embedded with what are called actuators, which, when pressurized with air, can contract and twist the sleeve — keeping the heart pumping.

Currently, the robot is a prototype that’s been tested in pigs. In trials, researchers used it with a pacemaker, “to trigger the actuation of the device, and simultaneously to pace the heart,” she notes. The hope is that with further testing, the robot could help humans with heart failure survive while waiting for a heart transplant.

“It's very much in the research phase,” Roche says. “And we have a lot more work to do in terms of optimizing the device and miniaturizing the hardware. And a lot more animal testing to do — long-term animal testing to make sure that it's safe to implant in humans. So, it'll definitely be a few years, but we're hoping to advance it along the path.”

While Roche’s team is using flexible robots to increase function for internal organs, others are working on ones that can be worn outside the body. Panos Polygerinos, an assistant professor of engineering at Arizona State University, helped design one robot that can help patients with hand impairments use their fingers to grasp.

“So, we're placing those soft, inflatable structures on top of their fingers,” he explains. “We're matching the anatomy of the finger. And when we are pressurizing them with some fluids … we can actually have the finger bend in synchrony with how we control the actuators.”

Polygerinos worked on the hand robot as a postdoctoral fellow at Harvard University, and he says the design team is looking for investors to make the robot commercially available.

Now, he’s working with students at Arizona State to design more soft robots. One project is an entire soft artificial limb, with a grasper on the end. He thinks that device could “even assist people that don’t have impairments, but they really need a third arm to execute tasks.”

Another device he’s working on supports the biceps of wheelchair users, who can suffer from muscular overuse. He says the soft robotic device will contract the same way our biological biceps do, giving users an extra “boost” without fatigue. He’s also recently started exploring soft orthotic devices (think braces or splints) to help users with impaired back muscles complete everyday tasks — and even play sports.

“So, for example, you go out on a Sunday to play golf, but you have instructions not to strain your back muscles too much,” he says. “So, wearing that device under your clothes might actually help you support the muscle groups that are in need so, that the soft robot can detect what you're doing and at exactly the correct time, give you that extra support.”

For the moment, soft robotics is an emerging field. But Polygerinos says that the customizable, pliant devices are attracting a lot of attention within the research community.

“It's going to be a few years before we start seeing prototypes and devices getting out there, but it's going to happen,” he says. “So, the future, I think, is bright.”

This article is based on an interview that aired on PRI's Science Friday.