http://www.abqjournal.com/328885/news/dod-wants-protocell-to-protect-soldiers-2.html
The protocell consists of a porous nanoparticle made of silica material that easily dissolves in the body. The particle is chock full of holes, or tubes, which can carry a range of drugs, including multiple medicines at the same time.
The exterior of the protocell is covered with a protective coating similar to the membranes that surround cells, plus a protein that allows them to bind with targeted tissue, such as cancer cells.
The membrane coating seals the drugs inside the protocell. And because the coating is biologically compatible with human tissue, the nanoparticle can float harmlessly in the bloodstream until it binds with targeted cells to release their cargoes inside the diseased tissue.