Biofilm developed to power wearable electronics with sweat
CategoriesSustainable News

Biofilm developed to power wearable electronics with sweat

University of Massachusetts Amherst researchers have invented a biofilm that sticks to the skin like a Band-Aid to harnesses sweat for electricity that could power wearable devices.

The biofilm is made using a bacteria that converts energy from evaporation into electricity, making use of the moisture on a person’s skin as it turns into vapour.

The University of Massachusetts Amherst researchers behind the innovation say it takes advantage of the “huge, untapped source of energy” that is evaporation.

“This is a very exciting technology,” said team member and electrical and computer engineering graduate student Xiaomeng Liu. “It is real green energy, and unlike other so-called ‘green-energy’ sources, its production is totally green.”

Microbial biofilm powers a small LCD screen with the word 'Hello' written on it
The biofilm uses sweat to power small electronic devices such as an LCD screen

According to the researchers, this is because the film is produced naturally by the microbes, with no need for unsustainably produced materials and no toxic waste byproducts.

“We’ve simplified the process of generating electricity by radically cutting back on the amount of processing needed,” said microbiology professor Derek Lovley, who is one of the senior authors of a paper the team has published in the journal Nature Communications.

“We sustainably grow the cells in a biofilm, and then use that agglomeration of cells. This cuts the energy inputs, makes everything simpler and widens the potential applications.”

The bacteria used is called geobacter sulfurreducens and is known for its ability to produce electricity, having previously been used to make microbial batteries.

Unlike with those batteries, however, the biofilm bacteria do not need to be periodically fed or cared for, because they are already dead — one of the team’s discoveries is that the microbes do not need to be alive to produce electricity.

To obtain the biofilm, the researchers harvest the geobacter, which grows in colonies that look like thin sheets of under 0.1 millimetres thickness, with the microbes all connected to each other by “natural nanowires”.

Diagram showing the biofilm sandwiched in between two layers of mesh electrodes and two layers of biopolymer
The biofilm is sandwiched between electrodes and sticky biopolymer before being ready for use

The researchers etch small circuits into these mats and then sandwich them between two mesh electrodes before sealing the package in a soft, sticky biopolymer to enable it to grip to the skin.

They describe the act of applying the film to your body as akin to plugging in a battery, and say it could revolutionise wearable electronics by solving the problem of where to put the power supply.

“Batteries run down and have to be changed or charged,” said electrical and computer engineering professor Jun Yao. “They are also bulky, heavy and uncomfortable.”

In its current form the biofilm produces enough energy to power small devices such as medical sensors or personal electronics, but the team also plans to explore larger films that can power even more sophisticated devices.

At an even larger scale, they hope the biofilm could be used to make more use of the untapped energy from evaporation, pointing to research that shows around 50 per cent of the solar energy reaching earth is spent on the process.

An example of a microbial battery appears in the work of Dutch designer Teresa van Dongen, who has used the geobacters to produce the Electric Life lighting and the Mud Well installation.

She embraces the fact that the bacteria need to be fed, arguing that this ritual would create “a closer relationship between the (living) object and its owner”.

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An energy-harvesting wearable made from recycled waste
CategoriesSustainable News

An energy-harvesting wearable made from recycled waste

Spotted: The global market for smart wearables is forecast to reach $42.3 billion (around €38.9 billion) by 2028. These devices will undoubtedly improve our lives through greater connectivity and convenience. But more electronic devices mean more demand for raw materials such as iron, copper, and gold – something which is increasingly emerging as a problem.

To tackle this, researchers from the University of Surrey, are explored how recycled waste materials can be used to make wearables by developing and testing a prototype wrist device made from discarded paper wipes and plastic cups.

The prototype is powered by energy harvested from the wearer’s movements. The device contains materials—called Triboelectric Nanogenerators (TENGs)—that become electrically charged when they rub against one another, in a process known as electrostatic induction. This charge is used to power the device – which currently transmits morse code. In the future the prototype could be developed into a smart watch.

“It won’t be long until we have to ask ourselves which of the items we own are not connected to the internet,” explains Dr Bhaskar Dudem, project lead and Research Fellow at the University of Surrey’s Advanced Technology Institute (ATI). “However, the current internet-of-things (IoT) revolution highlights the simple fact that our planet doesn’t have the raw resources to continue to make these devices which are in such high demand.”

Wearable innovations recently spotted by Springwise include
a biosensor
that can measure emotional data, a wearable
sensor for tracking stress, and a wearable
that uses the human body to power electrical equipment.

Written By: Matthew Hempstead

Email: mediarelations@surrey.ac.uk

Website: surrey.ac.uk

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