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MIT scientists design tiny motors powered by light

"Because our approach does not require shaping of the light field, a single beam of light can simultaneously actuate a large number of particles," researcher Ognjen Ilic said.

By Brooks Hays
Scientists simulated a new nanoparticle which spins and moves in reaction to simple light beams. Photo by Christine Daniloff/MIT
Scientists simulated a new nanoparticle which spins and moves in reaction to simple light beams. Photo by Christine Daniloff/MIT

June 30 (UPI) -- A team of engineers at MIT have simulated tiny motors powered by light.

Scientists have created a variety of light-based contraptions, including tractor beams and tweezers. But these optical technologies often require a sophisticated laser beam or some other kind of expensive and complex light source.

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"Our approach is to look at whether we can get all these interesting mechanical effects, but with very simple light," Ognjen Ilic, a postdoctoral researcher at MIT, said in a news update.

Ilic and his colleagues focused on designing a particle that could be powered and manipulated by simple light sources. The scientists simulated asymmetric particles known as Janus particles. The two-faced particles boast a micrometer diameter and are composed of silica. Half of each particle is coated in gold.

When exposed to light, the particles shift the axis of their symmetry in line with the beam. At the same time, the light-exposed particles begin to spin uniformly. By changing the color of the light, scientists found they can alter the particles' spin rate. A single beam can energize multiple particles at once.

Scientists suggests the optical nanomotors could be deployed in the body as part of new medical treatments. Their movements through and positioning within the body could be controlled by light.

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"Because our approach does not require shaping of the light field, a single beam of light can simultaneously actuate a large number of particles," Ilic said. "Achieving this type of behavior would be of considerable interest to the community of scientists studying optical manipulation of nanoparticles and molecular machines."

Researchers say their findings -- detailed in the journal Science Advances -- could be used in a variety of applications outside the medical field.

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