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Sweat-Powered Health Monitors? Whatever Next?

It was a very gloomy Sunday afternoon. It had been raining all day, and the wind was lashing the rain against the windows, through which I regarded my sodden garden.

Autumn was upon us, and I involuntarily shivered. We had just enjoyed a late lunch of warmed crusty bread rolls and Heinz’s cream of tomato soup, our go-to comfort food for afternoons such as this.

It was definitely a slobby Sunday, a day for curling up on the settee to enjoy a movie, or to catch up on the latest episodes of good TV shows.

We have currently been watching “Manifest” which appears to be a good show. Intriguing, and possibly quite plausible. I’m not sure where it’s going, but I will stick with it for the time being.

I picked up the remote and brought the TV to life. I was rewarded with a new advert for EE, one of the UK’s cellular networks. In this one, Kevin Bacon was promoting EE’s new 5G service.

In the advert, a barber was shaving a man’s face from a remote location.

To accomplish this, the barber, (located in Clapton in London, 250 miles away) was wearing a modified glove that was fitted with finger and wrist position sensors.

The man to be shaved, actor, Tom Ellis, was located on the top of Mount Snowdon in Wales, accompanied by a robotic arm, complete with articulated hand, capable of holding a shaving brush and a razor).

I was absolutley fascinated with this, watching as the barber, using a phone connected to the 5G network to see what he was doing, loaded a shaving brush with shaving soap, and then simultaneously saw the mechanical robot arm applying the soap to the man’s face, despite him being many miles away.

Subsequently, the barber picked up a cut-throat razor, and shaved the man’s face.

That’s a lot of trust, folks!

Now, I’m a bit of a sceptic, and am aware of how good CGI is, but it does link into my interest in the medical uses of 5G, so I decided to do some research.

My first port of call was the EE website, to see what they had to say about their latest campaign.

I was a bit blown away to discover that this was a REAL demonstration, and made no use of CGI, but instead used the EE 5G network and a custom-made robot arm.

Only recently, the world’s first (allegedly – you may know differently!) successful surgical procedure performed from a remote location was conducted in south east China, using the local Huawei 5G network.

5G is certainly going to change the way we live, but more about that in a later article.


The reason that I mention 5G here, is that it will no doubt have other uses in medicine and personal health care, especially when used in conjunction with wearable technology.

A few years ago, I carried a little more (lot more) weight than I do now, and my blood pressure was all over the place. As an incipient hypochondriac, I also suffer from a condition known as “White Coat Hypertension”.

I first discovered that I had this condition was at the renewal of my first Class 1 flying medical. My normally placid, mildly elevated blood pressure launched to positively near-death levels as soon as I sat on the chair in front of the medic.

Over the years, my blood pressure has been brought under control, and is consistently textbook normal.

Until I am having a flight medical. Then it’s at stratospheric levels again.

One of my doctors decided that I would need to undertake an ambulatory blood pressure check. This involved me wearing a bulky blood pressure monitor, complete with inflatable arm cuff, for a twenty-four-hour period.

During this time, the system would take recordings every ten minutes or so. I spent a miserable 24 hours walking round like Quasimodo.

At the end of the test, I was diagnosed with mild hypertension and was prescribed medication to deal with it.

Medical technology has advanced a lot since the early 1990s and now health monitoring systems have become a lot smaller and a bit more refined, but they still require a battery to power them.

However, digital wearable technology is now commonplace. Smart watches such as the Apple, Garmin and Fitbit models, which monitor many health factors including heartrate, blood pressure, blood oxygen levels, sleep tracking, electro-cardiogram (ECG) and physical activity.

Apple Smart Watch 5 Image Courtesy Raralu444 under CCA-SA 4.0

As wonderful as they are, these smart wearables are still limited by their need to carry their own power source – normally a rechargeable Lithium-Ion battery.

There are now developments that make this unnecessary.

A group of bioengineers working at UCLA* Samueli School of Engineering have developed a flexible magnetoelastic generator, that creates electrical power from the natural movements of the human body.

The principle is simple. If you remember your schoolboy (and schoolgirl!) physics lessons, you will probably recall that the interaction between magnets generates an electrical current.

The generator consists of a matrix of tiny magnets, woven into a stretchy, silicone sheet. When the sheet is flexed, the movement of the magnets against each other generates an electrical current.

Flexible, Stretchable, Self-Powered, Waterproof, magneto-elastic generator. Image Credit Jun Chen, UCLA

The sheet is flexible and soft enough that it may be worn comfortably against the skin. Movement of the muscles will flex the sheet, causing power to be generated. It’s even sensitive enough to create power from the tiny movements caused by a human pulse.

Impervious to sweat, or water, the system is quite capable of generating sufficient electricity to power a self-contained heart monitor, sweat monitor or thermometer.

Another recent system is a sweat-powered artificial skin, developed by researchers at Caltech’s Department of Medical Engineering.

Sweat-Powered Electronic Skin Image Credit – Caltech

This alternative method is based upon a soft electronic skin, or “e-skin” made of flexible rubber, into which are embedded several sensors together with what may only be described as bio-fuel cells.

Human sweat contains high levels of the chemical Lactate, which is a normal by-product of any form of metabolic activity, for example, from the activity of muscles when the body is conducting physical activity.

The bio-fuel cells built into the e-skin, absorb the sweat, and in the process capture the Lactate, which combines with Oxygen to produce water and Pyruvate. During the process, the biofuel cells generate electrical power.

The amount of energy generated is sufficient to power all the sensors woven into the e-skin and additionally, a Bluetooth© transceiver, which enables the e-skin to transmit sensor data to any Bluetooth© enabled device.

This useful technology will allow the remote monitoring of blood glucose levels, hormone levels, cardiac activity, body temperature and neural activity.

The same scientific team at Caltech, (led by Wei Gau Assistant Professor of Medical Engineering at the Andrew and Peggy Cherng Department of Medical Engineering) have also developed a system that uses kinetic energy to generate power for biomedical sensors.

To put it simply, a thin skin is created using layers of Teflon, Polyamide and Copper. This is attached to the person’s skin.

A further layer of Polyamide and Copper is allowed to slide back and forth over the skin’s layers, and induces an electric current. In the prototype, the team stuck the Teflon/Polyamide/Copper layer to the subject’s torso, and the sliding layer was secured to their arm, so that natural movement would trigger the generation of current.

Triboelectric Generator Prototype. Image Credit Caltech

This is known as a “Triboelectric Generator”.

Most of us will have experienced this at some point, when we have walked across a synthetic carpet, whilst wearing synthetic clothing. We build up an electric charge, which can then discharge to earth – sometimes quite painfully!

Now, all these human-powered sensors are in early stages of development, but in due course, they will become part of the Internet of Things (IOT), and will be using 5G to send real-time medical data to your family doctor, your diabetic or cardiac specialist or medical consultant.

Maybe they will even send biomedical data to the emergency services should you get cut whilst going to the barbers!

Brave new world?

You decide.

Go Well.

*University of California Los Angeles

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