If you manage to get one of the big corporate research institutes to tell you what they’ve looking at when it comes to graphene, the response is usually: sensors.



Now researchers at the University of Pennsylvania have leveraged both graphene and DNA to produce a new sensor that increase the sensitivity of diagnostic devices used to monitor HIV.

Just as in other uses of graphene for sensors, in this application graphene’s property of being only one-thick and highly conductive makes it extremely sensitive to detecting biological signals. The way the actual device exploits that property is that when DNA or RNA molecules bind to the graphene surface, they dramatically change the materials conductivity.

This is not the first time that this basic design has been used as a biological sensor. However, in this case instead of using a single-stranded DNA that can only bind to the target DNA molecule, they developed what they have dubbed a “DNA hairpin” in which its curled structure opens up when the target molecule binds to it.

When it opens, another DNA molecule that has been added to the system kicks the target molecule out, making it possible to bind with many different sites on the graphene.