Rotation of microspheres in a vertically changing external magnetic field. The color is switched between on (blue) and off states. Video courtesy Yin lab, UC Riverside

In the future, signs will be instantly rewritable and walls will change color at the flip of a switch. A research team at the University of California at Riverside has created a new magnetically activated, instantly and reversibly color-changing material with potentially groundbreaking applications. The technology is based on that used by colorful birds, beetles, and butterflies: instead of static pigments, the material employs "structural color," which depends on the interference effects of light.

The use of concrete dates back to ancient Rome, and the recipe hasn't changed much since then. Neither have some of concrete's drawbacks. In particular, the slow deformation known as "concrete creep" has afflicted structures from the Pantheon to the Pentagon. But MIT scientists believe they have solved the mystery of concrete creep, and thus opened the door to structures that will last tens of thousands of years.

For a few years now, we’ve been excited about the possibility of a cable-based space elevator as an alternative to expensive rocket launchers. To date, though, the various attempts to make it happen–including annual contests and Japan’s recent initiative–have come up short. The problem? Space elevators have one major hang-up: most designs call for braided cords of extremely strong nanotubes, which unfortunately don't exist yet.

Nanomotors hold the promise of one day powering tiny robots that could do everything from fighting viruses to cleaning up toxic waste. Thanks to some scientists at the University of Florida, that day is getting rapidly closer; and some of these robots might end up solar-powered.

A new paper published in the journal Nano Letters details how the researchers created the first light-powered nanomotor out of a photoreactive chemical and a short length -- only 31 base pairs -- of DNA.

Ever wished you could have Harry Potter's invisibility cloak? Science, not magic, could make that a reality. Researchers at the University of California at Berkeley have created materials that have the potential to bend light and even redirect it around themselves, cloaking any object behind them. They are metamaterials, materials that gain unusual properties via their structures. While all materials found in nature have a positive refractive index, these man-made metamaterials have a negative one.

Gun-slinging evil-doers beware. Scientific justice is just around the corner thanks to a new nanotechnology system that not only better captures DNA on guns, but attaches hard-to-remove, microscopic tags to the hands and clothing of criminals who fire their weapons. Developed in the U.K., the tags are a unique blend of naturally-occurring pollen, known for its extraordinary adhesive properties, and nanotechnology particles.

Catching cancer before it metastasizes, or spreads throughout the body, is one way to increase your chances of survival. Now scientists may have found a way to help even when cancer is already on the move, by using magnets to lasso cancer cells and drag them out of the body. Researchers at the Georgia Institute of Technology have shown that magnetic nanoparticles—tiny shards of magnetic metal, less than a hundred thousandths of an inch in diameter—can be attached to cancer cells, which can then be manipulated and moved with another magnet.

In the strange, subatomic world of quantum mechanics, even complete nothingness exerts a force. According to a principle known as the Casimir Effect, two plates separated by an incredibly small space will experience a force pushing them together. While the Casimir effect isn’t powerful enough to affect daily life, it has complicated efforts to build effective nanotechnology.