Tiny threads that teach brain cells to grow

Samuel Stupp's team at Northwestern University built molecule-sized threads so precisely patterned they coax neurons to grow longer and form more connections — without any drugs. The negatively charged segments attract the body's own growth proteins, tapping against the cells thousands of times a second and switching on their growth machinery. Published in Science, the work could one day help repair damaged nerves. 'We discovered something we had never seen before in chemistry or in biology,' Stupp said.