Navigation Links
Graphene nanoribbons for 'reading' DNA

If we wanted to count the number of people in a crowd, we could make on the fly estimates, very likely to be imprecise, or we could ask each person to pass through a turnstile. The latter resembles the model that EPFL researchers have used for creating a "DNA reader" that is able to detect the passage of individual DNA molecules through a tiny hole: a nanopore with integrated graphene transistor.

The DNA molecules are diluted in a solution containing ions and are driven by an electric field through a membrane with a nanopore. When the molecule goes through the orifice, it provokes a slight perturbation to the field, detectable not only by the modulations in ionic current but also by concomitant modulation in the graphene transistor current. Based on this information, it is possible to determine whether a DNA molecule has passed through the membrane or not.

This system is based on a method that has been known for over a dozen years. The original technique was not as reliable since it presented a number of shortcomings such as clogging pores and lack of precision, among others. "We thought that we would be able to solve these problems by creating a membrane as thin as possible while maintaining the orifice's strength", said Aleksandra Radenovic from the Laboratory of Nanoscale Biology at EPFL. Together with Floriano Traversi, postdoctoral student, and colleagues from the Laboratory of Nanoscale Electronics and Structures, she came across the material that turned out to be both the strongest and most resilient: graphene, which consists of a single layer of carbon molecules. The strips of graphene or nanoribbons used in the experiment were produced at EPFL, thanks to the work carried out at the Center for Micro Nanotechnology (CMI) and the Center for Electron Microscopy (CIME).

"Through an amazing coincidence, continued the researcher, the graphene layer's thickness measures 0.335 nm, which exactly fits the gap existing between two DNA bases, whereas in the materials used so far there was a 15 nm thickness." As a result, while previously it was not possible to individually analyze the passage of DNA bases through these "long" tunnels at a molecular scale , the new method is likely to provide a much higher precision. Eventually, it could be used for DNA sequencing.

However they are not there yet. In only 5 milliseconds, up to 50'000 DNA bases can pass through the pores. The electric output signal is not clear enough for "reading" the live sequence of the DNA strand passage. "However, the possibility of detecting the passage of DNA with graphene nanoribbons is a breakthrough as well as a significant opportunity", said Aleksandra Radenovic. She noted that, for example, the device is also able to detect the passage of other kinds of proteins and provide information on their size and/or shape.

This crucial step towards new methods of molecular analysis has received an ERC grant and is featured in an article published today in Nature Nanotechnology.


Contact: Aleksandra Radenovic
Ecole Polytechnique Fdrale de Lausanne

Related biology news :

1. High-resolution atomic imaging of specimens in liquid by TEM using graphene liquid cell
2. Using graphene, scientists develop a less toxic way to rust-proof steel
3. Graphene plasmonics beats the drug cheats
4. Researchers use graphene quantum dots to detect humidity and pressure
5. MindSpec launches online Autism Reading Room
6. New model of disease contagion ranks US airports in terms of their spreading influence
7. Flightless molecule may prevent cancer from spreading from 1 tissue to another
8. Frequent traveller: Dysentery-causing bacteria spreading from Europe to Australia
9. Brain-wave-reading robot might help stroke patients
10. New book on stereology by Mark West is essential reading for neurobiologists
11. Joint UT study: Reading food labels helps shoppers stay thinner
Post Your Comments:
Related Image:
Graphene nanoribbons for 'reading' DNA
(Date:11/19/2015)...  Although some 350 companies are actively involved in ... companies, according to Kalorama Information. These include Roche Diagnostics, Hologic, ... share of the 6.1 billion-dollar molecular testing market, according ... Molecular Diagnostic s .    ... by one company and only a handful of companies ...
(Date:11/17/2015)... Paris from 17 th ... Paris from 17 th until 19 th ... leader, has invented the first combined scanner in the world ... scanning surface. Until now two different scanners were required: one ... both on the same surface. This innovation is an ...
(Date:11/17/2015)... , Nov. 17, 2015 Pressure BioSciences, ... in the development and sale of broadly enabling, pressure ... life sciences industry, today announced it has received gross ... $5 million Private Placement (the "Offering"), increasing the total ...  One or more additional closings are expected in the ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... ... 2015 , ... Copper is an essential micronutrient that all ... copper is also toxic to cells. With a $1.3 million award from the ... a systematic study of copper in the bacteria Pseudomonas aeruginosa (P. aeruginosa), a ...
(Date:11/24/2015)... ... November 24, 2015 , ... This fall, global software solutions ... in five states to develop and pitch their BIG ideas to improve health and ... are competing for votes to win the title of SAP's Teen Innovator, an all-expenses ...
(Date:11/24/2015)... Nov. 24, 2015 /PRNewswire/ - Aeterna Zentaris Inc. ... that the remaining 11,000 post-share consolidation (or 1,100,000 ... (the "Series B Warrants") subject to the previously ... November 23, 2015, which will result in the ... effect to the issuance of such shares, there ...
(Date:11/24/2015)... 2015 /CNW Telbec/ - ProMetic Life Sciences Inc. (TSX: PLI) ... Pierre Laurin , President and Chief Executive Officer of ... Piper Jaffray 27 th Annual Healthcare Conference to be ... 2015. st , at 8.50am (ET) and ... the day. The presentation will be available live via a ...
Breaking Biology Technology: