Nano-Tweezers Can Move Molecules With Light

Just in case you were getting bored with the world, we bring you a tiny tweezer made of light beams.

Tiny tweezer
The nano-tweezer is made by focusing a beam of laser light through a metal-coated optical fiber.Berthelot et al / Nature Nanotechnology

Scientists have created the tiniest "tweezers" known to date, which can move around objects the size of single molecules with a "bow tie" of light.

"To my knowledge these are the smallest tweezers ever built," physicist Mathieu Juan, from Sydney's Macquarie University, told the Australian Broadcasting Corp. "They will allow people to manipulate, scan and move around very small objects such as viruses."

In a study describing the technology, published in Nature Nanotechnology, the scientists were able to move a plastic sphere--that was only 50 nanometers wide, roughly 1,000 times thinner than a human hair--over significant distances. It works like this, according to ABC:

The researchers focused a beam of laser light through a metal-coated optical fibre. At the tip of the fibre they created an opening shaped like a bowtie, made of two overlapping triangles. It's the shape of this opening that allows the beam of light to be controlled with such "exquisite precision," says Juan. The device is based on a mechanism known as "self-induced back action", he explains. In essence, this means that optical tweezers are designed to shape themselves to the presence of the object they are picking up.

The technology could be used to assemble tiny structures or physically manipulate molecules like DNA, the researchers said. Unlike previous technologies, it doesn't increase the temperature of tiny molecules, which are vary sensitive to heat and pressure.