India, June 27 -- Ever had a sinus infection that just wouldn't go away? Now imagine a day when, instead of popping antibiotics or trying home remedies, your doctor sends a swarm of tiny robots up your nose to clear out the infection. Sounds wild, right? But researchers in China and Hong Kong are actually making it happen, and the science is moving faster than you'd think.

These robots are so small you can't even see them with the naked eye. They're thinner than a strand of hair. During tests on animals, scientists managed to get these micro-robots into the sinus cavity using a very fine tube through the nostril. Once inside, a magnetic field guides them straight to the trouble spot.

Here's where it gets clever. The robots are made with...