More nanofilters that separate molecules

Mr_Farlops writes "In something of a reprise of earlier work involving silica nanotubes, scientists at UC Davis have developed a switchable polycarbonate membrane etched with tiny, evenly-sized pores. The pores, only 10 nanometers across, are lined with a thin layer of gold and then with another layer of oily molecules called thiols. The thiols spontaneously assemble into a switchable membrane that can be opened or closed according to the acidity of the solution on one side or the other of the membrane. The researchers envision the use of these membranes in microscopic "labs-on-a-chip," inexpensive sorting of catalysts and enzymes or in the controlled release of tiny quantities of drugs."