Liquid logic

日期:2017-07-18 04:06:10 作者:牛浣 阅读:

By Lila Guterman in Florence CHEMICALS that function like electronic circuits on a silicon chip can now compute responses to up to three separate inputs. These molecular logic gates respond to the presence or absence of the inputs by emitting coloured light. Some of these chemical switches are made up of molecules that light up when they grab a molecule from the surrounding solution. Others turn off when certain molecules are present. Already, such simple YES and NO logic gates are being used as sensors that monitor acidity levels or the concentration of sugar in blood. A few years ago, A. P. de Silva and his colleagues at Queen’s University of Belfast designed a chemical AND logic gate—a molecule that lights up only if it detects two different ions at once. Now he has pushed molecular logic a step further, with a NOR gate and an INHIBIT gate. The NOR molecule lights up only if neither mercury ions nor protons are present in solution. INHIBIT lights up when it senses both calcium ions and organic molecules called cyclodextrins—but the presence of oxygen turns the light signal off. Vincenzo Balzani, a chemist at the University of Bologna in Italy, says these molecular analogues of electronic devices are important research tools, even if they don’t ultimately result in a chemical computer. “It introduces new ideas to chemistry,