nanopump_A charge-driven molecular water pump

abstract:

Understanding and controlling the transport of water across nanochannels is of great importance for designing novel molecular devices, machines and sensors and has wide applications1, 2, 3, 4, 5, 6, 7, 8, 9, including the desalination of seawater5. Nanopumps driven by electric or magnetic fields can transport ions10, 11 and magnetic quanta12, but water is charge-neutral and has no magnetic moment. On the basis of molecular dynamics simulations, we propose a design for a molecular water pump. The design uses a combination of charges positioned adjacent to a nanopore and is inspired by the structure of channels in the cellular membrane that conduct water in and out of the cell (aquaporins). The remarkable pumping ability is attributed to the charge dipole-induced ordering of water confined in the nanochannels13, 14, where water can be easily driven by external fields in a concerted fashion. These findings may provide possibilities for developing water transport devices that function without osmotic pressure or a hydrostatic pressure gradient.

(Nature Nanotechnology
Published online: 21 October 2007 | doi:10.1038/nnano.2007.320)