In the presence of ultraviolet light, the nanoparticle
shrinks from 150 to 40 nanometers.
As anyone who has played with a powerful laser or just suffered a bad sunburn can attest, light has an impressive power to physically change objects. And now we know that light can make nanoparticles expand and contract like miniature Hoberman Spheres. MIT and Harvard researchers engineered nanoparticles that shrink to less than a third of their original size when exposed to ultraviolet rays; in the darkness or under visible light, they open back up to their more stable, larger size.
Nanoparticles have been touted as an effective way to deliver cancer-killing drugs straight to tumors without harming healthy cells in the process. But the structure of a tumor can block all but the smallest particles—those less than 100 nanometers (billionths of a meter)—from penetrating to the cancer’s heart. To deliver drugs to the entire tumor, the researchers suggest that the particles could be deployed while UV light keeps them in their smaller form, about 40 nanometers. Then, when the UV light is switched off, the particles will open to their full 150-nanometer size and release the drugs.
What’s the News: The reproductive life of a cuckoo is both easy—it lays its eggs in others birds’ nests, and lets them feed the young—and difficult: cuckoos are involved in an “evolutionary arms race” with other birds, finds a new study. Even as cuckoos improve their counterfeiting skills—producing eggs that look more like others birds’—the host birds get better and better at identifying the forged eggs.
How the Heck:
What’s the Context:
The Future Holds: Scientists still aren’t sure why some hosts, like the dunnock, are so accepting of cuckoo eggs. Some scientists argue that this is because the risk in mistakenly rejecting a real egg outweighs the cost of raising a cuckoo egg. The jury’s still out.
Reference: “AVIAN VISION AND THE EVOLUTION OF EGG COLOR MIMICRY IN THE COMMON CUCKOO” Mary Caswell Stoddard and Martin Stevens. DOI: 10.1111/j.1558-5646.2011.01262.x