We already know what a wondrous material graphene can be – filtering water, dyeing hair, super-strengthening substances – but now scientists have figured out a way to produce it much more cheaply: with the help of bacteria.
When mixed with oxidised graphite, which is relatively easy to produce, the bacterium Shewanella oneidensis removes most of the oxygen groups and leaves conductive graphene behind as a result. It's cheaper, faster, and more environmentally friendly than existing techniques to make the material.
Using this process, we might be able to create graphene at the sort of scale necessary for the next generation of computing and medical devices – utilising graphene's powerful mix of strength, flexibility, and conductivity.
"For real applications you need large amounts," says biologist Anne Meyer from the University of Rochester in New York.
"Producing these bulk amounts is challenging and typically results in graphene that is thicker and less pure. This is where our work came in."
Using the new method, Meyer and her colleagues were able to make graphene that's thinner, more stable, and longer-lasting than graphene that's produced by chemically manufacturing.
This opens up all kinds of possibilities for the cheaper, bacteria-produced graphene. It could be used in field-effect transistor (FET) biosensors, devices that detect particular biological molecules, such as glucose monitoring for diabetics.
Because the bacteria production process usually leaves behind certain oxygen groups, the resulting graphene is well-suited to being able to bind to specific molecules – exactly what an FET biosensor needs to do.
This kind of graphene material could also be used as a conductive ink in circuit boards, in computer keyboards, or even in small wires to defrost car windshields. If needed, the bacteria process can be tweaked to produce graphene that's only conductive on one side.
Graphene was first produced by using sticky tape to extract it from graphite blocks. Nowadays it's made via a number of different chemical methods that are applied to graphite or graphene oxide, but this newly discovered technique could be the most promising one yet – and without any of the harsh chemicals.
As this is the first study to investigate the bacteria approach, plenty more research will need to be done before it can be scaled up and used to build the next generation of laptops. Nonetheless, the future of this incredible material continues to look bright.
"Our bacterially produced graphene material will lead to far better suitability for product development," says Meyer.
The research has been published in ChemistryOpen.