Soft Robots Mimic Muscle to Expand the Body’s Limits

11:51 minutes

A demonstration of the sequential squeezing and twisting action of the robotic sleeve. Credit: Ellen Roche
A demonstration of the sequential squeezing and twisting action of the robotic sleeve. Credit: Ellen Roche

Heart failure affects some six million adults in the United States. The disease results when weakened heart muscle isn’t able to flush blood and oxygen through the body’s circulatory system to the organs that depend on it. But what if failing hearts could get a robotic assist? Researchers have now developed a prototype that can do just that—in pigs. The squishy robot fits around the heart like a sleeve and keeps blood pumping, even after a heart attack. Ellen Roche and her team describe the device in the journal Science Translational Medicine.

Soft robots like this could some day compensate for our bodies’ weaknesses, inside and out. Other researchers, like Panos Polygerinos, are developing external devices that can guide weakened hands or beef up bicep strength. In this segment, Roche and Polygerinos talk about their vision for our future selves, augmented by soft robots.

The prototyped soft robotic glove for users with hand impairments. The range of motion that can be achieved is shown here. Credit: Panagiotis Polygerinos
The prototyped soft robotic glove for users with hand impairments. The range of motion that can be achieved is shown here. Credit: Panagiotis Polygerinos

Segment Guests

Ellen Roche

Ellen Roche is a post-doctoral researcher at the National University of Ireland in Galway, Ireland.

Panos Polygerinos

Panos Polygerinos is an assistant professor in the School of Engineering at Arizona State University in Phoenix, Arizona.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. How about a break from politics? Are you ready for some really interesting science? We’ve got some really interesting stuff for you this hour.

How about a robotic heart assistant? You know, heart failure affects nearly six million adults in the United States. It strikes when the heart weakens and can no longer flush enough blood and oxygen through the body to the tissues and the organs that need it. But what if you could give the heart a little robotic assist, a little extra squeeze to help it do what the muscle is too weak to accomplish by itself?

That’s exactly what my next guest has invented– a squishy robot that fits around the heart and can help broken hearts pump blood again. For now, though, it’s only working in pigs being tested. Ellen Roche is the lead author on the work published in the journal, Science Translational Medicine She’s a postdoctoral researcher at the National University of Ireland. Welcome to Science Friday, Dr. Roche.

ELLEN ROCHE: Hi, how are you? Thanks for having me.

IRA FLATOW: You’re welcome. Can you describe for us how this thing works exactly? It fits around the heart like a cup holding it?

ELLEN ROCHE: Yeah, of course. It’s kind of like a sleeve that fits on the outside of the heart, and it helps the heart to pump without contacting the blood. So it’s made of a silicone matrix with embedded actuators, and when you pressurize them with air, it makes the device contract and twist. And this helps the heart pump blood in heart failure patients.

IRA FLATOW: So it’s like a little pacemaker is attached to it to make it squeeze?

ELLEN ROCHE: Yeah. Actually, in our trials, we used a pacemaker to trigger the actuation of the device and simultaneously to pace the heart so that we knew that the device and the heart were in synchrony.

IRA FLATOW: Can you actually restart the heart after a heart attack?

ELLEN ROCHE: So typically after a heart attack, there’s a procedure called stenting, where the heart is reperfused, or the vessels that kind of open to restart the heart. But what can happen is that scar tissue can form, and the heart can go into heart failure. So when the patient gets to end stage heart failure, when they’re not responding to medical management anymore, they get on a transplant list. And this device would act as a bridge to transplant to kind of help them to improve the pumping function of the heart while they’re waiting to get a heart transplant.

IRA FLATOW: Of course, what everybody wants to know is when will this be tested out in humans?

ELLEN ROCHE: Of course, yeah. So at the moment it’s very much in the research phase, 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.

IRA FLATOW: And it would be for people, I’m assuming, who are already experiencing heart failure.


IRA FLATOW: Yeah. Let me bring on another guest now, another innovator who’s designing flexible bots that can assist muscles on the outsides of our bodies too. Panos Polygerinos is an assistant professor in the School of Engineering at Arizona State University in Mesa, Arizona. Welcome to Science Friday.

PANOS POLYGERINOS: Hello, thank you for having me.

IRA FLATOW: You’re welcome. Now I know that you’re looking at some ways robots might help us move other muscles besides the heart, like in the hand with a robotic glove. Tell us about that.

PANOS POLYGERINOS: Yes, of course. Similar to what Ellen has done to help the heart function and pump blood again, what we are trying to do is utilize soft actuators that consist of elastomeric chambers. And the idea over there is to put those on top of your fingers in people that have hand impairments, and they are in need of hand rehabilitation or they require their hands to function to perform activities of daily living.

So we’re placing those soft, inflatable structures on top of their fingers. We’re matching the anatomy of the finger, and when we are pressurizing them with some fluids– for example, air– we can actually have the finger bend in synchrony with how we control the actuators. So that enables them again to grasp objects and perform activities of daily living.

IRA FLATOW: How close are you to having something that might actually be available to people?

PANOS POLYGERINOS: I would say that– first of all, I must give credits to Harvard and the biodesign lab. I was working on that as a post-doctoral fellow with Professor Conor Walsh. And they are taking this over, along with the Wyss Institute in Boston, and we are trying to find potential investors to have this be a commercially available product for people that are in need of these type of devices. We have done our first trials, and we’re moving ahead towards that.

IRA FLATOW: Now I understand that you’re actually creating an artificial limb, almost sort of like a third arm, right?

PANOS POLYGERINOS: Yes. Now as an assistant professor at Arizona State University, I’m exploring other pathways on how we could assist all of these people that are suffering from pathologies on their limbs. And one of these things is– one of these ideas that we are developing with my students right now is to have a limb, a soft limb, that branches up out of your body and has a soft grasper in the end, soft actuators again, that allows you to control it in way that you want to be controlled and assist you soon grasping objects or even assist people that don’t have impairments, but they really need of a third arm to execute tasks that are in need of a third hand.

IRA FLATOW: And you’re also working on, similar to that, a sort of bicep booster, an add on robot that makes your bicep muscles stronger. Or this sort of like a biotic person?

PANOS POLYGERINOS: Yeah. The idea start started with some clinicians that we are working with, and they were looking on how to decrease overused muscle syndromes for the shoulder of users on wheelchairs. So the idea is these users keep using their shoulders a lot, and they end up having problems with that. So how can we have soft muscles that can contract in a similar way that our biological biceps operate to actually give you that extra boost at the time that you need it to help you keep going without getting the fatigue on your muscles?

IRA FLATOW: Ellen Roche, it’s sort of like these soft robots are like physical therapists who massage you mechanically by a robot instead of having a real person, inside and out.

ELLEN ROCHE: Yeah, exactly. That’s kind of one of the goals of these soft robotic devices so they can augment the native function of different organs and parts of the body while being atraumatic and conformable and not causing any damage to the body.

IRA FLATOW: What makes all of these devices robots? They look a lot different from what people might think of as a robot.

ELLEN ROCHE: Sure, yeah. They’re very different from conventional robots with the rigid parts, but they’re robotic in the sense that you can program them to achieve pre-defined motions. So you can just decide what motion you want to achieve, and you pressurize them, but you design them so that they will move in a certain way.

For example, in the heart sleeve, we’ve oriented the actuators so that they mimic that of the muscle of the heart. So we have circumferential and twisting actuators so that when we pressurize them they squeeze and twist at the same time–

IRA FLATOW: Wow. I’m sorry

ELLEN ROCHE: –and, yeah. I was going to say in Panos’ glove, he can speak to that as well.

PANOS POLYGERINOS: Yeah. So soft robotics in general is giving us a lot of more advantages that we cannot get through rigid, traditional robotic systems. Everybody is thinking of a robot as being something huge, bulky, very strong. So the idea right now is how can we use different type of materials that are softer, that are more compliant, they match the soft tissue of a human being to interact with the human brain and be inherently more safe, decrease that cost of developing those devices.

And most importantly, as Ellen said, we can customize the actuation based on patients’ anatomy or based on the needs that that patient has. So these are some of the benefits that soft robotics are bringing. That’s why they are attracting a lot of attention lately because we need to develop better systems, and all researchers around the globe are trying to figure out how we can make those better.

IRA FLATOW: You know, I’m sort of thinking of these robots being used by older adults who have weakened muscle strength. They have trouble getting out of a chair, or standing, or walking, help them from falling backwards or forwards. Is this might– Panos, might this be use a for this?

PANOS POLYGERINOS: Oh, definitely. So there is another idea that we have started recently exploring in my lab, which is how can we create, let’s say, a soft orthotic devices for strengthening your back muscles.

That might be for– useful or so besides impaired users, it could be for people that are doing sports. So for example, you go out on a Sunday to play golf, but you have instructions not to strain your my back muscles too much. So wearing that device under your clothes might actually help you support the muscle groups that are in need. So the robot, the soft robot, can detect what you’re doing and at exactly the correct time, give you that extra support that you are in need. And these are, again, some of the examples.

IRA FLATOW: Ellen, I would imagine that these devices have to be pretty intelligent and able–

ELLEN ROCHE: Yeah, definitely.

IRA FLATOW: able to adjust their own activity as the body changes and have a good feedback mechanism through the body.

ELLEN ROCHE: Yeah. Well, at the moment, our devices is user controlled. So we would– when the device is being placed, the cardiac surgeon would look at the heart beating and synchronize the actuation of the robot with the heart. And then as the patient– the vision is as the patient– as the disease condition of the patient evolved, they could use imaging to assess how the native heart is functioning and then tune the actuation depending on what the patient needs.

So at the moment there isn’t an in-depth kind of feedback mechanism. it will be done by a surgeon or a doctor that’s treating the patient.

IRA FLATOW: Yeah. We don’t hear much about soft robots. This is interesting. Panos, you know?

PANOS POLYGERINOS: Yeah. It is indeed. As you might know, this is a relatively new field in robotics. It doesn’t count many, many years, but nevertheless, as I said earlier, it has attracted a lot of attention in the research community at least. It’s going to be a few years. Yeah, it’s gonna be few years before we start seeing prototypes and devices getting out there, but it’s going to happen. So the future, I think, is bright. We’re going to have these new types of robots that people are not used to and these are going to be part of our lives.

IRA FLATOW: We’ll have to change it from Iron Man to plastic mercury man or soft man, something like that. Thank you, Dr. Roche. Thank you, Panos. Ellen Roche is postdoctoral researcher at the National University of Ireland, and Panos Polygerinos is an assistant professor in the School of Engineering at Arizona State University.

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