Graphene from a test tube
Bacteria help to get nanomaterial for future computers
Scientists from the UK and the Netherlands have come up with a new way to get nanomaterials from graphene: mix oxidized graphene and bacteria. Their method is economical, requires less time, and also does not harm the environment, compared to the chemical production of the material. The method can lead to the creation of innovative computer technologies and medical equipment, according to the website of the University of Rochester (Will your future computer be made using bacteria?). An article with the results of the study was published in the journal ChemOpen (Lehner et al., Creation of Conductive Graphene Materials by Bacterial Reduction Using Shewanella Oneidensis).
To create new and more efficient computers, medical devices and other advanced technologies, researchers are turning to nanomaterials – materials controlled at the scale of atoms or molecules that have unique properties. One of these revolutionary compounds is graphene, a two–dimensional form of carbon. This thin carbon flake has extraordinary mechanical strength and flexibility and is able to easily conduct electricity. Nevertheless, we cannot actively use graphene in everyday life yet: it is very difficult to produce it on a large scale. And not only from an economic point of view: graphene obtained in large quantities is denser and loses its unique properties.
Graphene is extracted from graphite, a material that is used in an ordinary pencil. With a thickness of exactly one atom, graphene is the thinnest and at the same time the most durable two-dimensional material known to science. In 2010, scientists from the University of Manchester received the Nobel Prize in Physics for pioneering experiments with graphene: they were able to obtain graphene by delaminating graphite with a simple adhesive tape. However, their method yielded a small amount of material.
To produce more graphene materials, a group of researchers led by Anne Meyer, associate professor of biology at the University of Rochester, started with a bottle of graphite. They gradually exfoliated graphite to graphene oxide, which was then mixed with Shewanella bacteria. They left a bottle with bacteria and graphene oxide overnight, during which the bacteria turned the material into graphene by removing oxygen groups.
In the photo from left to right: a bottle with graphite (Gr), as in a regular pencil; a bottle with graphene oxide (GO), obtained by exfoliating graphene and mixing it with Shewanella bacteria; a bottle with the resulting product – graphene material (mrGO); and a bottle with graphene material, which was obtained chemically (crGO).
Graphene oxide itself does not conduct electricity well, but it is easy to produce. And graphene obtained with the help of bacteria is not only a good conductor, it is also much thinner and more stable than chemically obtained graphene. In addition, it can be stored much longer.
Graphene nanomaterial has many applications. It can be used for the production of field-effect transistor (FET) biosensors. FET biosensors are devices that detect biological molecules and can be used, for example, to monitor glucose in real time in diabetic patients.
The graphene material obtained by bacteria can also be the basis for conductive ink, which, in turn, can be used to create faster and more efficient computer keyboards, circuit boards or small wires. According to Meyer, the use of conductive ink is "a simpler and more economical way to produce electrical circuits compared to traditional methods." Conductive ink can also be used to create electrical circuits on top of non-traditional materials such as cloth or paper.
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