Illustration for article titled Sequencing DNA just got easier

A specialized form of graphene could be used to ‘read' a long strand of DNA like ticker tape.


Graphene, mentioned on Io9 for being perfect for computer parts, invisibility cloaks, and lightweight, thin body armor, and mentioned on for being perfect for biosensors, has added yet another possible skill to its resume. It can help quickly and inexpensively sequence DNA.

Sequencing DNA is often a time-consuming and expensive process. Many copies of DNA strands are ripped apart into shorter strands. The base sequences of the shorter strands are painstakingly determined. Once all of the short strands are analyzed, a computer looks for common sequences and uses them to reorder the short strands into the original complete strand of DNA. The process is a little like taking many copies of a thousand-piece jigsaw puzzle and mix all the pieces together before trying to re-order them and see the original picture.

Graphene could make the process much, much easier. The DNA strand wouldn't have to be copied or broken down into shorter pieces. Graphene, it turns out, is very well-suited to coming into contact with DNA. Under some conditions, in fact, it can protect DNA from breaking or getting torn apart.


Graphene can be made into sheets one atom thick. The sheets are strong, relatively easy and cheap to make, and conduct electricity. Once the sheets are made, an electron beam can poke holes in them. A strand of DNA is then pushed through the holes, like thread through the eye of a needle. Since the sheet is so thin, only one base – A, C, T, or G – touches the graphene at a time.

While the DNA is moving through the graphene, an electric current is moving through it as well. Graphene conducts electricity well. So well, in fact, that any other material mixed with the graphene will provide some resistance. Every different kind of material will provide a different kind of resistance. Since only one base touches the graphene at a time, each of the bases will produce a different level of overall conductivity in the material. By measuring the fluctuations in the electric current in the graphene as a strand of DNA moves through it, researchers could ‘read' the DNA as it slides through the material.


Via and Physics World

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