Google Pill

"Google Working on Pill That Searches for Illnesses"

[T]he pill is packed with tiny magnetic particles, which can travel through a patient's bloodstream, search for malignant cells and report their findings to a sensor on a wearable device.  As many as 2,000 of these microscopic "nanoparticles" could fit inside a single red blood cell to provide doctors with better insights about what is happening inside their patients.