Nanoparticles injected into brain tissue. This image shows two types of nanoparticles that have been injected into brain tissue. The new 60-nanometre nanoparticles (red), which are densely coated with a non-adhesive, non-toxic polymer, are spreading away more efficiently from the site of injection compared to conventional adhesive, charged particles (purple) of the same size. The image was obtained through a real-time cranial window. This work was carried out by researcher at the Johns Hopkins University Center for Cancer Nanotechnology Excellence (CCNE), USA. Image produced in 2013.