The nucleus is the headquarters of a cell and molecules constantly move across the nuclear membrane through pores. The transport of these molecules is both selective and fast; some 1,000 molecules per second can move in or out. Scientists from the University of Groningen and Delft University of Technology, both in the Netherlands, and a colleague from the Swedish Chalmers University of Technology, have developed an artificial model of these pores using simple design rules, which enabled them to study how this feat is accomplished. Their results were published on 31 March in Nature Communications.