"By measuring the flow of ions passing through a nanopore drilled in graphene we have demonstrated that the thickness of graphene immersed in liquid is less then 1 nanometer thick, or many times thinner than the very thin membrane which separates a single animal or human cell from its surrounding environment," said lead author Slaven Garaj of the Department of Physics at Harvard University.

"This makes graphene the thinnest membrane able to separate two liquid compartments from each other."

"The thickness of the membrane was determined by its interaction with water molecules and ions."

Graphene's remarkable properties have attracted interest from many researchers.

As well as being the strongest material known to science, it is electrically conductive.

"Although the membrane prevents ions and water from flowing through it, the graphene membrane can attract different ions and other chemicals to its two atomically close surfaces," said co-author Professor Jene Golovchenko of Harvard.

"This affects graphene's electrical conductivity and could be used for chemical sensing,"

"I believe the atomic thickness of the graphene makes it a novel electrical device that will offer new insights into the physics of surface processes and lead to a wide range of practical application, including chemical sensing and detection of single molecules."

Several challenges still remain to be overcome before DNA sequencing with graphene is practical, including controlling the speed with which DNA threads through the nanopore.

When achieved, graphene could lead to very inexpensive and rapid DNA sequencing.

"We were the first to demonstrate DNA translocation through a truly atomically thin membrane," said co-author Professor Daniel Branton of Harvard University.

"The unique thickness of the graphene might bring the dream of truly inexpensive sequencing closer to reality."

"The research to come will be very exciting."