Roland Piquepaille writes "Chemists from the University of California at Riverside designed two years ago a molecule which could move straight on a flat surface — a nano-walker if you wish. Now, they've found a way to force this walking molecule to carry packages. The nano-worker can now carry two CO2 molecules. And like yourself when you carry two heavy bags, this nano-worker is slower when it carries other molecules. The researchers think their discovery will lead to reliable ways of carrying molecules, an equivalent of the conveyor belts in today's factories."