Optical tweezers build tiny on-chip structures

Optical tweezers build tiny on-chip structures

Using light beams as tweezers, two researchers at the Massachusetts Institute of Technology (Cambridge, MA) have been able to hold and move around individual cells and other objects on the surface of an opaque microchip. The technologistsMatthew J. Lang, an assistant professor in the Departments of Biological Engineering and Mechanical Engineering, and David C. Appleyard, a graduate student in Biological Engineeringbelieve the technique could become an important tool for both biological and materials research.

Appleyard points out that the approach would allow researchers to merge optical trapping with silicon technology. For example, he notes, many people are now studying how neurons communicate by randomly depositing them on microchips, where electrical circuits etched into the chips monitor their electrical behavior, and hoping the neurons land on or near a sensor. With the new technique, neurons could be precisely positioned with respects to the circuits and thereby eliminate trial and error and reduce uncertainty in measurement.

Key to making the optical tweezer work for manipulating objects as small as a few nanometers on chips is that silicon is transparent to infrared wavelengths of lightwhich can be easily produced by lasers, and used instead of the visible light beams. For more information about this development, call Elizabeth A. Thomson of M.I.T. at 617-258-5402, or e-mail thomson@mit.edu.

Richard Comerford