Two scientists from the Massachusetts Institute of Technology have found a way to use light beams for picking up, holding, and moving around cellular and microscopic objects on a microchip, MIT announced Tuesday.
Matthew J. Lang, assistant professor of MIT's biological and mechanical engineering departments, and David C. Appleyard, graduate student in the biological engineering department, determined that using infrared light on select silicon wafers is a way to use optical tweezers as a tool for manipulating objects on microchips.
The breakthrough could have applications in both the biology and electronics industry, according to Lang.
While the idea of optical tweezers has been around for about 30 years, it has necessitated a transparent glass surface in order to work and was, therefore, not applicable to opaque silicon chips. Lang and Appleyard hypothesized that silicon wafers are transparent to infrared wavelengths of light and thought that might be a way to solve the dilemma. The only problem was that the two were initially unsure which types of silicon wafers might work with the new method.
As silicon wafers are expensive and usually only available in bulk, the scientists posted help-wanted signs around MIT. They were able to initially test their theory on used silicon wafers discarded by scientists working on other projects. Once they determined which ones worked best, they then ordered them for the next phase of the project.
The system can work on cells within the nanometer-to-micrometers range, the common range of all living cells, according to Appleyard. The scientists have also been able to move a hollow object that was 20 micrometers and manipulate 16 E. coli cells on a microchip to spell out the letters "MIT."