Credit: ©2011. Johns Hopkins Department of Neurosurgery. All rights reserved. Ian Suk
During surgery to excise a brain tumor, direct access to the brain and the space in between its cells is possible. Conventional nanoparticles carrying chemotherapeutic drugs can be applied during the surgery, but they essentially remain on the surface where they are applied (red arrows). Nanoparticles coated with a sufficient amount of PEG have the capacity to diffuse through the tissue (purple arrows) so that they can migrate towards the individual tumor cells that have escaped from the tumor mass.