A new approach to treating cancers and other diseases that uses a mechanically interlocked molecule as a ‘magic bullet’ has been designed by researchers at the University of Birmingham. Called rotaxanes, the molecules are tiny nanoscale structures that resemble a dumbbell with a ring trapped around the central post. This new design uses a much larger cylindrical-shaped supramolecular ‘helicate’ molecule — around 2nm long and 1nm wide — which have remarkable ability to bind Y-shaped junctions or forks in DNA and RNA. In laboratory tests, the Birmingham researchers have shown that, when they bind to the junctions, the cylinder molecules are able to stop cancer cells, bacteria and viruses from reproducing. The results are published in the Journal of the American Chemical Society.