Direct sunlight kills a lot of things pretty well on its own. A lot of multicellular organisms that spend much time in the sun have all sorts of adaptations to deal with it.
I think we're obliged at this point to bring up the cancer concerns that are always present when dealing with nano-scale particles. Can these nanoflakes break off? I know the asbestos problems were when breathed in, are there also problems with drinking them? A very interesting product, though.
I'd like to see some science fiction endings for this.