The week's In The News addresses a recent advancement in the scientific field of molecular nanotechnology. The scientists, Nadrian Seeman and colleagues, at New York University (NYU), have built a nano-robotic prototype from synthetic DNA. This recent major accomplishment was also reported in Nature, (Nature 397: 144-146, Jan. 14, 1999). This controllable molecular mechanical device has "two rigid DNA 'double-crossover' molecules connected by a long DNA helix of 4.5 double-helical turns that can be rotated from the normal B-form of (right-handed) DNA to Z-form of (left-handed) DNA when the solution is changed by increasing the salt concentration or adding certain small effector molecules such as cobalt hexamine." A flip of six nanometers between the two arms ("double-crossover" molecules) is observed when cobalt hexamine is added. Nadrian Seeman and colleagues conclude that it is possible to "incorporate this mechanical control in any figure or array produced by DNA nanotechnology, so long as free swivel containing proto-Z DNA can be included in the design." This development could lead to the construction of nano-robots that may manufacture or repair molecules possibly within the human body. The seven resources discussed provide US and international news resources as well as background information and recent advancements made in molecular nanotechnology.