A byproduct of making the drink kombucha can be used to create flexible electronic circuits that could be useful for wearable technology or even for making simple computers that are partially alive.
More than 60 types of bacteria and yeast are involved in brewing kombucha from sugared tea 鈥� these form a mat of cells on top of the drink. This mat is usually transferred to fresh batches of sweetened tea, where it converts sugars into alcohols and then acids to create the drink鈥檚 taste.
at the University of the West of England, Bristol, and his colleagues have now found that when dried, the mat of cells can be used to create flexible circuit boards.
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The researchers printed circuits onto dried mats using two methods: with an aerosol jet of a conductive polymer and using a 3D printer to lay down a conductive mix of polyester and copper.
In tests, Adamatzky and his team incorporated 3-millimetre and 5-millimetre LEDs into the circuits by attaching them with silver-impregnated epoxy adhesive. The circuits still worked after repeated bending and stretching.
The researchers say that kombucha circuits are lighter, less expensive and more flexible than conventional electronic systems and could be used in a diverse range of applications including wearable devices, such as heart rate monitors.
Dried mats are feasible as a base for circuit boards because they are non-conductive, so the electrical current stays in the printed circuit. However, research has revealed that living kombucha mats are conductive and can react to stimuli by .
They have also been found to create , so could potentially be used as sensors, with printed circuits to link them to other components. This might mean they could be used to make partially living rudimentary computers, says Adamatzky.
鈥淣owadays kombucha is emerging as a promising candidate to produce sustainable textiles to be used as eco-friendly bio wearables,鈥� he says. 鈥淲e will see that dried 鈥� and hopefully living 鈥� kombucha mats will be incorporated in smart wearables that extend the functionality of clothes and gadgets. We propose to develop smart eco-wearables which are a convergence of dead and alive biological matter.鈥�
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