Taking advantage of recent advances in nanotechnology and microfluidics, researchers have made significant progress toward a device that could be used to rapidly remove pathogens from the blood of patients with sepsis, a potentially life-threatening condition that occurs when an infection is distributed throughout the body via the bloodstream. The new system effectively acts as an artificial spleen, filtering the blood using injectable magnetic nanobeads engineered to stick to microörganisms and toxins. After the beads are injected, blood is removed and run through a device that uses a magnetic-field gradient to extract the nanobead-bound germs. Then the blood is returned to the body.