Nanotechnology, the manufacture and use of structures and implements of around a few 100 nm in size, is becoming a key technology of the twenty-first century. An important element for the manufacture of nanoparticles is gold. Gold nanoparticles can be custom made and chemically modified in their size and form. Initial investigations have shown that they are physiologically non-hazardous. A potential application is in neovascular age-related macular degeneration. Gold nanoparticles of suitable dimensions introduced into newly forming blood vessels can be targeted and heated which selectively destroys these blood vessels. This principle has already been demonstrated in cultivated endothelial cells.