In their presentation the researchers outlined experiments conducted in mice with carbon nanotubes designed to detect insulin, key for diagnosing diabetes; fibrinogen, a protein necessary for blood clot formation and an indicator of liver disease or other inflammatory diseases; and nitric oxide, a molecule the body produces if cancer is present. The researchers engineered the polymers to sense a particular molecule. They tested the carbon nanotubes in blood samples outside the mice, then they implanted the devices inside the mice. The nanotubes worked—they transmitted a continuous signal and, when inside the body, didn't break down or cause a reaction for 400 days. The nitric oxide sensors in particular worked well, as they were injected into the bloodstream and were even able to pass through the tiny capillaries in the lungs.