Silver nanowires. Coloured atomic force micrograph (AFM) of silver nanowires (red). The nanowires lie about 20 nanometres apart on a calcium fluoride crystal. They were assembled from clusters of several thousand silver atoms using the tip of the AFM. Nanowires could be used for miniature electronics or as a substrate for growing artificial tissue. Atomic force microscopy involves scanning an object by moving a spring- loaded 'stylus' over it. Magnification: x250,000 at 6x4.5cm size.