Credit: Image courtesy of Lawrence Livermore National Laboratory
Illustration of a high water flow going through a narrow carbon nanotube stylized as a water pipe. When embedded in fatty membranes, the nanotubes squeeze entering water molecules into a single file chain, which leads to very fast transport. The flow was 10 times faster than in wider carbon nanotubes and 6 times faster than in the best biological membrane, a protein called aquaporin. Nanotubes were also highly selectivity for positively charged ions—even in seawater-like solutions.