Some of the most exciting medical research these days involves light. Light therapy for cancer, in which a tumor-seeking dye becomes toxic as soon as a light is switched on, manages to avoid slaughtering nearby healthy cells
---using light to turn on or off the expression of neurons---has advanced researchers' understanding of neurological diseases. Now, a recent paper
is a reminder that light might someday be used for exquisitely tailored drug delivery: in this paper, tiny packages bearing all the molecular machinery to build a protein are idle when injected into mice, but spring into action when exposed to UV light. The nanoparticles, which you can see a schematic of above, are little envelopes of cellular membrane, wrapped around a basic set of protein-building machinery and the gene for whatever you'd like manufactured---the researchers used a glowing fluorescent protein for their test. The gene can't be accessed by ...
