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Graphene nanoribbons for ‘reading’ DNA


Nov. 17, 2013 — If we wished to rely the selection of folks in a crowd, lets make on the fly estimates, very prone to be imprecise, or lets ask every individual to move via a turnstile. The latter resembles the adaptation that EPFL researchers have used for making a “DNA reader” that is ready to realize the passage of particular person DNA molecules via a tiny gap: a nanopore with built-in graphene transistor.

The DNA molecules are diluted in an answer containing ions and are pushed through an electrical box thru a membrane with a nanopore. When the molecule goes throughout the orifice, it provokes a moderate perturbation to the sector, detectable no longer simplest by using the modulations in ionic present but additionally with the aid of concomitant modulation within the graphene transistor present. According to this knowledge, it’s conceivable to resolve whether or not a DNA molecule has handed in the course of the membrane or now not.

This technique is in keeping with a technique that has been recognized for over a dozen years. The unique method was once no longer as dependable because it offered quite a lot of shortcomings similar to clogging pores and shortage of precision, amongst others. “We idea that we might be capable to resolve these issues with the aid of making a membrane as skinny as imaginable whereas sustaining the orifice’s potential,” mentioned Aleksandra Radenovic from the Laboratory of Nanoscale Biology at EPFL. Along side Floriano Traversi, postdoctoral pupil, and colleagues from the Laboratory of Nanoscale Electronics and Buildings, she got here throughout the fabric that grew to become out to be each the strongest and most resilient: graphene, which contains a single layer of carbon molecules. The strips of graphene or nanoribbons used within the scan have been produced at EPFL, because of the work performed on the Middle for Micro Nanotechnology (CMI) and the Heart for Electron Microscopy (CIME).

“Via an excellent twist of fate, persisted the researcher, the graphene layer’s thickness measures zero.335 nm, which precisely matches the hole current between two DNA bases, whereas within the supplies used thus far there used to be a 15 nm thickness.” Consequently, whereas prior to now it used to be no longer that you can imagine to in my opinion analyze the passage of DNA bases thru these “lengthy” tunnels — at a molecular scale -, the brand new way is probably going to supply a a lot larger precision. Sooner or later, it may be used for DNA sequencing.

Then again they don’t seem to be there but. In handiest 5 milliseconds, as much as 50’000 DNA bases can move in the course of the pores. The electrical output sign isn’t clear sufficient for “studying” the are living sequence of the DNA strand passage. “Alternatively, the potential of detecting the passage of DNA with graphene nanoribbons is a step forward in addition to a major chance,” mentioned Aleksandra Radenovic. She cited that, as an instance, the device can be ready to observe the passage of different types of proteins and supply knowledge on their measurement and/or form.

This an important step against new strategies of molecular prognosis has acquired an ERC provide and is featured in a piece of writing printed lately in Nature Nanotechnology.