Taking up the sci-fi staple of "tractor beams," scientists have developed a way to use light to grab and move minuscule particles on a microchip. The research could lead to fine-grained biological sensors and other precisely built nanoscale devices.

The work by Massachusetts Institute of Technology researchers could extend the possibilities for "optical tweezers" _ super-focused beams of light that have been used for years to study and manipulate tiny biological structures or even individual atoms.

Optical tweezers have been used on transparent media _ like a microscope slide _ that let the light shine through and hold objects in a tractor beam-like embrace. (This is possible because light's individual photons transfer minuscule amounts of force to particles they hit.)