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. Optogenetics—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 the machinery because it is sealed into a loop by a piece of molecular adhesive, but shine a UV light on it, and the adhesive unsticks. Then the machinery transcribes the gene, and the protein is expressed. The researchers found that when they injected the particles into mice and turned on the UV light, the injection site glowed.
Though we’re far from swapping drugs or medically helpful proteins into these remote-control nano-factories just yet, showing that they can function in a live animal is an exciting advance.