Looking a bit like annoying logic puzzles, these rotaxane shapes could change the world of medicine – and electronics, too, for that matter. Each tiny device has a rotating ring (coloured gold here) that is free to slide up and down a dumbbell shape (blue). It might not sound like much, but rotaxanes can be slotted into machines as rotors or ratchets. Now the really clever part – these rotaxanes are made from folded strands of DNA, 100,000 times smaller than those fiddly metal puzzles. DNA origami uses the DNA’s code to create edges and ends that stick together automatically; making millions of these devices is a matter of a few chemical reactions. So if you’re looking to make a tiny motor to fit inside a cell, or a molecular bomb that releases drugs inside a tumour, this might be a vital piece in your design.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.