Biobattery-embedded tattoos to use sweat to power your tech

Scientists have developed a temporary tattoo with a built-in, sweat-powered biobattery that could one day be used to charge your phone while you are out for a run.

The biobattery works using lactate, a key chemical found in sweat that can be used to monitor exercise performance.

This means that the more the wearer sweats, the more energy is going to be produced, creating the interesting scenario where less physically fit people are able to produce more power.

The technology is one of the first examples of skin-based power sources, and could pave the way for a host of technologies powered by devices attached to the skin.


The biobattery works by using an enzyme to extract the electrons in the sweat’s lactate and move them to the battery. At present, the amount of energy produced is very small, but the researchers are confident that they will be able to develop this to enable small electronic devices to be charged.

“The current produced is not that high, but we are working on enhancing it so that eventually we could power some small electronic devices,” said Dr Wenzhao Jia, a postdoctoral researcher at the University of California San Diego.

“Right now, we can get a maximum of 70 microWatts per cm², but our electrodes are only 2 by 3 millimeters in size and generate about 4 microWatts — a bit small to generate enough power to run a watch, for example, which requires at least 10 microWatts.

“So besides working to get higher power, we also need to leverage electronics to store the generated current and make it sufficient for these requirements.”

The device has also been developed as a lactate monitor, which will be a valuable tool for both doctors and athletes. Previously lactate has been monitored using a series of blood tests, so this monitor is likely to prove simpler and less invasive.

The biobattery’s reliance on sweat means that the amount of power produced can vary significantly depending on the person wearing it.

The researchers tested the initial biobattery on 15 exercise bike-riding volunteers, and found that not only did those who were least fit produce the most energy, but the most regularly active participants produced the least energy.

This could affect the potential success of the technology, as such variation in performance could make it difficult to market.

However, this is one of the first examples of skin-based batteries, and the technology is likely to be developed much further.

“These represent the first examples of epidermal electrochemical biosensing and biofuel cells that could potentially be used for a wide range of future applications,” said Dr Joseph Wang, professor of nanoengineering at University of California San Diego.

From here we could see the development of an array of wearable technologies and gadgets siphoning power through our skin, perhaps even one day powering whole computers, medical augmentations and more.

Inline image courtesy of Dr Joseph Wang.

Could this be the blueprint for future city living?

Later this year, a housing development that could form the model for how many of us live in the future is opening in the UK’s capital.

Described by those behind the project, property startup The Collective, as the “world’s largest purpose built co-living scheme”, it will blend the shared nature of student living with the amenities and quality of a luxury hotel, providing everything from room cleans and linen changes to WiFi and concierge services.

Aimed at young people working in the city, the development in Old Oak, west London, it is designed to encourage communal living, or as The Collective describes it, Co-Living.


Although the apartments are the size of a hotel room – featuring a double bed, desk, kitchenette and an en-suite bathroom – the communal areas are sizeable, totalling 10,000sqft.

In addition to communal kitchens and living areas for each floor, the development will include a gym, spa, cinema and an array of restaurants. And at £250 a week per apartment with utilities and council tax included, while it isn’t the cheapest option in the city, it will sit happily in the price range of many Londoners.

“Our Old Oak development is offering Londoners a fresh and innovative way of living – it’s also a much needed option in the context of the capital’s housing crisis.  We are changing the way people can choose to live,” said Reza Merchant, CEO of The Collective.

The shared aspect of the development is likely to appeal to many young people, offering a far greater sense of community.

And with other facilities including a rooftop terrace, games room and a coffee shop, it’s set to feel more like a village than a block of flats.

You can even work in the development too, as there will be a 400-person shared working space available from September.


Images courtesy of The Collective.

This provision of communal living is particularly beneficial given the level of isolation that urban living can often provide, and if the residents get on well, many could see an improved quality of life from such an environment.

“We’re offering a solution that will enable young working Londoners, who are the lifeblood of the UK economy, to live properly, enjoy themselves and meet like-minded people,” said Merchant. “Co-living creates a genuine sense of community alongside access to so many more amenities than you would get in a flatshare.”

Combine the communal appeal with both the convenience of the service and the growing shortage of affordable urban housing in cities around the world, and the project looks set for widespread replication.

DARPA is sending brain implants on a voyage round the body to power artificial limbs

A DARPA-funded research team has created a brain implant that can be transported to the brain through blood vessels and take control of artificial limbs.

The new device – dubbed the stentrode –was developed under DARPA’s Reliable Neural-Interface Technology (RE-NET) program, and offers new potential for safely expanding the use of brain-machine interfaces to treat physical disabilities and neurological disorders.

“DARPA has previously demonstrated direct brain control of a prosthetic limb by paralyzed patients fitted with penetrating electrode arrays implanted in the motor cortex during traditional open-brain surgery,” said program manager for RE-NET, Doug Weber.

“By reducing the need for invasive surgery, the stentrode may pave the way for more practical implementations of those kinds of life-changing applications of brain-machine interfaces.”


Traditional brain implants have been implanted into the brain through invasive surgical procedures that require opening the skull.

However, because of the stentrode’s flexibility and durability it can transported via blood vessels, which are used as portals for accessing deep structures while greatly reducing the trauma associated with open surgery.

Proof-of-concept results, from a study conducted in sheep, are described in an article published in Nature Biotechnology.

The article describes how measurements taken from the motor cortex using the stentrode are quantitatively similar to measurements made by commercially available brain implants that require open-brain surgery.

Image and featured image courtesy of DARPA

Image and featured image courtesy of DARPA

The research into brain-machine interfaces is the defence agency’s latest foray into the health industry having previously created an artificial limb, which communicates directly with the wearer’s neural system, a prosthetic hand that can connect directly to the brain and a number of tiny implantable nerve stimulation devices that can monitor, diagnose and treat the nervous system.

Super-strong, super-stretchy material to be used as artificial skin

A new stretchy material has been developed that can lift an object one-thousand times its weight while still maintaining the ability to revert back to its original shape, when heated at body temperature.

Scientists at the University of Rochester believe that because of its flexibility their shape-memory polymer will be used as artificial skin but could also be useful when applying sutures, for body-heat assisted medical dispensers and for use as a wearable self-fitting apparel.

“Our shape-memory polymer is like a rubber band that can lock itself into a new shape when stretched,” said lead researcher, Mitch Anthamatten. “But a simple touch causes it to recoil back to its original shape.”

Image and featured image courtesy of Adam Fenster, University of Rocheste

Image and featured image courtesy of Adam Fenster, University of Rocheste

The shape-memory polymer works by controlling the crystallisation that occurs when the material is cooled or stretched.

As the material is deformed, polymer chains are stretched, and small segments of the polymer align in the same direction in small areas called crystallites.

These crystallites fix the material into a temporarily deformed shape, but as the number of crystallites grows, the polymer shape becomes more and more stable, making it increasingly difficult for the material to revert back to its initial shape.

To avoid the material becoming fixed in a deformed state the research team inserted molecular linkers to connect the individual polymer strands.

Anthamatten’s group discovered that linkers inhibit, but don’t stop, crystallisation when the material is stretched.

By altering the number and types of linkers used, as well as how they’re distributed throughout the polymer network, the university researchers were able to adjust the material’s structure and precisely set the point at which the material’s shape can be reverted.


As well as being able to stretch and revert back to its original shape the new material has been optimised so that it can store as much elastic energy as possible.

As a result, the shape-memory polymer is capable of lifting an object one-thousand times its weight. For example, a polymer the size of a shoelace – which weighs about a gram – could lift a litre of soda.

“Tuning the trigger temperature is only one part of the story,” said Anthamatten. “We also engineered these materials to store large amount of elastic energy, enabling them to perform more mechanical work during their shape recovery”

Full details of the shape-memory polymer can be found in the Journal of Polymer Science Part B: Polymer Physics.