A graphic illustration shows single nucleotides passing through a molybdenum disulfide nanopore film while controlled with a viscous room-temperature ionic liquid. Credit: Aleksandra Radenovic/EPFL
Story highlights
- Researchers develop method for improved and low cost DNA sequencing.
- Method uses molybdenum disulfide film
- Researchers are seeking to commercialize nanoporous membrane.
(2D Materials Magazine)- Researchers at EPFL in Switzerland have developed a method that they state improves the accuracy of DNA sequencing up to a thousand times-and is a lot cheaper than current methods. The method utilizes nanopores that read DNA as it passes through. Nanopore sequencing has to now been largely inaccurate due to the speed at which DNA usually passes through .
EPFL scientists have now discovered a viscous liquid that slows down the process up to a thousand times, vastly improving the method’s resolution and accuracy.
Molybdenum disulfide film
The lab of Aleksandra Radenovic at EPFL’s Institute of Bioengineering have overcome the traditional speed problem by using a molybdenum disulfide (MoS2) film that slows the passage of DNA two to three orders of magnitude. As a result, sequencing accuracy improves down to single nucleotides. The team then created a nanopore on membrane, almost 3 nm wide.
The next step was to dissolve DNA in a thick liquid that contained charged ions and whose molecular structure can be fine-tuned to change its thickness, or “viscosity gradient”. The liquid belongs to the class of “room-temperature ionic liquids”, which are basically salts dissolved in a solution. The EPFL scientists exploited the liquid’s tunability to bring it to an ideal viscosity gradient – enough to slow down DNA.
Finally, the team tested their system by passing known nucleotides, dissolved in the liquid, through the nanopore multiple times. This allowed them to take an average reading for each one of the four nucleotides, which can be used to identify them later on.
Commercialization
Although still at a testing stage, the team is aiming to continue their work by testing entire DNA strands. They are seeking opportunities to commercialize this technique, which is promising for sequencing with solid-state nanopores according to one of the researchers.
The scientists also predict that using high-end electronics and control of the viscosity gradient of the liquid could further optimize the system. By combining ionic liquids with nanopores on molybdenum disulfide thin films, they hope to create a cheaper DNA sequencing platform with a better output.
Reference
Feng J, Liu K, Bulushev RD, Khlybov S, Dumcenco D, Kis A, Radenovic A. Identification of single nucleotides in MoS2 nanopores.Nature Nanotechnology 21 September 2015. DOI: 10.1038/nnano.2015.219
