New material could enhance fast, accurate DNA sequencing

Gene-based personalized medicine has many possibilities for diagnosis and targeted therapy, but one big bottleneck: the expensive and time-consuming DNA-sequencing process.

Now, researchers at the University of Illinois at Urbana-Champaign have found that nanopores in the material molybdenum disulfide (MoS2) could sequence DNA more accurately, quickly and inexpensively than anything yet available.

"One of the big areas in science is to sequence the human genome for under $1,000, the 'genome-at-home,'" said Narayana Aluru, a professor of mechanical science and engineering at the U. of I. who led the study. "There is now a hunt to find the right material. We've used MoS2 for other problems, and we thought, why don't we try it and see how it does for DNA sequencing?"

As it turns out, MoS2 outperforms all other materials used for nanopore DNA sequencing -- even graphene. Most materials used for nanopore DNA sequencing have a sizable flaw: They are too thick. Even a thin sheet of most materials spans multiple links of the DNA chain, making it impossible to accurately determine the exact DNA sequence.

Graphene has become a popular alternative, since it is a sheet made of a single layer of carbon atoms -- meaning only one base at a time goes through the nanopore. Unfortunately, graphene has its own set of problems, the biggest being that the DNA sticks to it. The DNA interacting with the graphene introduces a lot of noise that makes it hard to read the current, like a radio station marred by loud static.

MoS2 is also a single-layer sheet, thin enough that only one DNA letter at a time goes through the nanopore. In the study, the Illinois researchers found that DNA does not stick to MoS2, but threads through the pore cleanly and quickly.