[horns blaring] - [Presenter] The first documented artificial limb dates back to Ancient Rome and General Marcus Sergius, who had a prosthetic hand made of iron so he could hold his shield in battle.

Yes, he's known as the first Iron Man.

[marching music] Engineering evolved up to the Civil War when amputations were still the only viable option for many soldiers rooted in the field.

In 1866 North Carolina became the first of the Confederate states to offer artificial limbs to its Veterans.

The Jewett Leg Company was established in Raleigh where it offered limbs to over 1,500 amputees.

It had some moving parts, but not much else.

[retro music] - To be able to actually use them again, it's kind of odd.

- [Presenter] Greg Phillips lost his leg below the knee in 2013 after a motorcycle accident.

- So as soon as you do push off.

- [Presenter] Researchers at NC State and UNC Chapel Hill are working on a revolutionary device that may change how artificial limbs are engineered.

- So things that are difficult with a normal prosthesis like picking something up off the ground or like carrying a heavy load to the ground, even going from sitting to standing is difficult sometimes because with a normal prosthesis you don't have the flexibility.

You don't have that control.

Try to do toes up.

[gentle music] - [Patient] For me, the most difficult part was learning how to fire off those muscles again.

After seven years of not using the muscles at all, you know, they succumb to atrophy and just become flabby.

- [Presenter] The team is designing a prosthesis that actually follows a user's commands by responding to the signals sent from their brain.

If it works, that would be a major breakthrough.

Right now most prosthesis are attached to the limb and stay static, only moving if the limb moves.

The ankle joint is the key part of what makes this new limb unique.

The team has engineered a system to help mimic normal muscle behavior so they can test what works.

No one knows when it will be available to the public.

The biggest challenge now is making it a lot smaller.

[gentle music] So how does it work?

Sensors are placed in the front and the back of the leg.

The sensors detect signals sent from the brain to the muscle.

The muscles now control the direction of the ankle.

Air is then pushed into tubes around the ankle and those tubes work just like muscles.

- [Therapist] So this is in a normal prosthesis, he wouldn't have the flexibility that this ankle does.

Instead, what you would see is the heel to actually come up off the ground.

So by having the flexibility and the control he's using his own effort and he has the flexibility to squat down as far as he wants.

- [Presenter] Retraining the brain to establish a symbiotic relationship between a human and a machine can be tough and that's why neurological scientists are part of the team.

- Our research is very, you know, unique that we need multidisciplinary collaborations.

So, you know, as an engineer we know how to make the device and make the control work.

We know how to collect the data, analysis the data, but that's not enough.

As a part of the body limb we wanted to use this device naturally, right, sensor those device naturally.

That required this connections seamless interface between the human and the device.

[machine buzzing] - [Presenter] And for that, Wong and Fleming turned to Frank Hodges, a clinician who's been fabricating prosthetics for decades.

- There has to be a little bit of interpretation as to what they're feeling and what needs to be done and that's when it gets a little tricky.

- [Presenter] He needed to figure out how to engineer a prosthetic socket that would be comfortable but also sensitive enough for signals to travel back and forth between the sensor and the ankle motor.

- Sometimes their feedback isn't direct to the problem.

Sometimes it's a referring pain or just a feeling that they get of unsteadiness.

[gentle music] - So there's a huge question that needs to be answered of what does it take for someone to regain function using those muscles to actually effectively control a prosthesis.

- [Presenter] And Greg Phillips wants to help answer that huge question.

He says that while he won't be able to take one of these things home, he says if someone down the road can, he's proud to be part of that process of discovery.

- [Therapist] Nice.

- [Patient] It's still incredible that those feelings haven't been there for seven years.

[gentle music]