writes "A beam of electrons can pick up and carry nanoparticles, according to a new study (abstract). The so-called electronic tweezers could help scientists in diverse tasks, such as building up new materials nanoparticle-by-nanoparticle, and measuring the forces between nanoparticles and living cells, the researchers say. In the past, scientists have manipulated microsized particles, including single cells, using a beam of laser light called optical tweezers. But the force required to trap a particle with optical tweezers increases as the particle gets smaller, making grappling with nanoparticles difficult. Researchers at Lawrence Berkeley National Laboratory developed an alternative to optical tweezers by modifying a transmission electron microscope, which produces images by passing a stream of electrons through a sample."
Reader Sven-Erik adds news of a tractor beam generated with laser light
that can pull microscopic particles over distances of 30 micrometers (abstract