You're probably familiar with the 1966 science fiction film "Fantastic Voyage", where a submarine crew are shrunk to microscopic size and venture into the body of an injured scientist to repair damage to his brain. They're not quite at the stage of shrinking scientists yet, but engineers in America have invented a flexible robot - thinner than a piece of thread - that can be controlled using a magnetic field and snake its way through blood vessels to track down and remove blockages. Phil Sansom spoke to inventor Xuanhe Zhao... Like this podcast? Please help us by supporting the Naked Scientists