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Biological Samples and Graphene
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Graphene Enables Spectroscopy to Study Biological Samples

Some of the best tools we have for seeing matter down on the molecular scale, where a lot of the interesting things happen, have been electron microscopy and spectroscopy. 

However, they can’t be used effectively with biological specimens because the instruments would kill the specimen through either the vacuum they need to be placed in or the electron beam that needs to bombard them. The only way around the problem was to put them in a container known as a “liquid stage” that is wedged between two thick windows of silicon nitrate to protect the sample from the vacuum and use a low-energy beam that produces images of poor resolution.

Now researchers at University of Illinois in Chicago (UIC) have developed a method whereby a biological specimen can be sandwiched between two sheets of graphene and be protected in both electron microscopy as well as spectroscopy.

The graphene’s high thermal and electrical conductivity removes both the heat and electrons generated by the beam as it passes through the sample. As a result, higher energy electron beams can be used on the sample, resulting in higher resolution images. 

The graphene sandwich was demonstrated on a sample of ferritin, which is a protein. For the first time, this technique enabled the imaging of iron oxide in the core of the ferritin and the changing of its electric charge, leading to the release of iron. This new insight alone into how ferritin operates could help to better understand how a dysfunctional ferritin works towards triggering life-threatening diseases in the brain and other parts of the human body.