Nanoparticles that never have to enter the body can capture harmful components in blood, scientists in Switzerland have shown.Removing unwanted molecules from the blood is the most direct way to cure or prevent many illnesses. An example of this approach is dialysis where small molecules like urea are filtered out to treat patients with renal failure. As this separation method is size-selective, larger noxious molecules or cells cannot be efficiently eliminated from the blood in this way.Nanoparticles with capturing agents attached to their surface can remove larger molecules from blood. However, the risks of nanoparticles inside the body are not...