“Atomic-scale Lego” creates single-atom width capillaries that act like natural protein channels

Sir Andre Geim, co-discoverer of graphene and Nobel laureate, led the team at the University of Manchester’s National Graphene Institute which developed the artificial channels, capable of blocking hydrated ions larger than around 7A (0.7nm) in diameter. “Obviously, it is impossible to make capillaries smaller than one atom in size,” Geim explained. “Our feat seemed nigh on impossible, even in hindsight, and it was difficult to imagine such tiny capillaries just a couple of years ago.”

The channels, made using a technique known as van der Waals assembly or “atomic-scale Lego”, are 3.4A in height, allowing water molecules (2.8A in diameter) to pass through but blocking even the smallest hydrated ions, such as K⁺ and Cl^-, which are 6.6A in diameter because the ions themselves are surrounded by a shell of water. The technique was developed as a result of research on graphene, and the team explains its technique in the journal Science.