Department of Physics and Astronomy

Press release: A new type of nano-sensor detects DNA building blocks

2017-02-13

Researchers from Uppsala University and Brazil have developed a new type of nano-sensor that can detect single molecules. The nano-sensor, comprising a combination of two different materials, has been used to identify the different building blocks in DNA.

A molecule's dipole moment affecting the electrical potential of an atomic chain and thus altering the electrical current in the material. Figure: Ralph Scheicher.

What is really groundbreaking about this study is that it succeeded to combine in the same two-dimensional material the two substances graphene, which is electrically conductive, and boron nitride, which is insulating. Previously, these two substances have so far only been used separately in an attempt to detect molecules.

The detection of individual molecules is of great importance in medicine and health care, but currently available methods are generally too complicated and overly expensive to be used widely.

The study has applied the nano-sensor to detect the four naturally occurring nucleotides, which are the building blocks of DNA, and thus discovered a new quick and inexpensive way to sequence DNA by measuring an electric current.

In computer simulations, a little hole, called a nanopore, was created at the interface between the two substances, and a small chain of electrically conductive material thus formed between the nanopore and the insulating boron nitride. When molecules move through the hole, the electric potential of the chain is modulated and the conductivity of the material is therefore affected. By measuring the electric current in the material, the molecules can be identified through their characteristic dipole moment.

The study also included hydrogen fluoride, a small molecule with a large electric dipole moment, which is an ideal model system to get a better understanding of how the nano-sensor can detect the larger and more complex molecules.

“Computer simulations were carried out in vacuum, and the molecules were fixed relative to the carbon chain and nanopore. In future studies, we want to examine the dynamic aspects of the system. It will be exciting, for example, to see how the sensors react to water”, says Ralph Scheicher, assistant professor in materials theory at the Department of Physics and Astronomy. 

Fábio A. L. de Souza, et al; Electrical detection of nucleotides via nanopore in hybrid graphene/h-BN sheet, Nanoscale, 2017, DOI: 10.1039/C6NR07154F 

Contact 

Ralph Scheicher, assistant professor at the Department of Physics and Astronomy, Uppsala University, ralph.scheicher@physics.uu.se, +46 18-471 5873

Camilla Thulin

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