Tweezing at the Nanoscale

Like a decorator placing cherries atop a fresh-baked cake, scientists used light-based nanotweezers to precisely position six silver balls, each a thousandth the width of a human hair, in a ring. Credit: Linhan Lin.

What gets measured at the nanoscale can be both mind-bogglingly small and incredibly important. Think of the transistors powering a computer chip, about 1,000 of which can fit across the width of a human hair, or critical parts of the machinery within human cells. Soon, however, people may start manipulating nanoscale objects like these, using a light-based innovation spearheaded by a team of University of Texas at Austin engineers and physicists.

In much the same way that mechanical tweezers handle something precise like a splinter, the new tool, nicknamed “nanotweezers,” handles nanoparticles using light and heat. Already the researchers have used the tool to successfully trap polystyrene beads, silicon nanowires, metal nanostructures and more. They envision the next frontier opening a new chapter in nanomedicine wherein live cells are manipulated, perhaps to communicate with one another or to shift molecules so as to improve drug release.

Ernst-Ludwig Florin, associate professor of physics and a member of UT’s Center for Nonlinear Dynamics, along with graduate student Emanuel Lissek, precisely measured, evaluated and demonstrated the strength of the nanotweezers, conceived of by Yuebing Zheng from the Cockrell School of Engineering, using a state-of-the art custom microscope developed by Florin. The opto-thermoelectric nanotweezers are already giving scientists insights into how matter organizes and could pave the way for the discovery of new functional materials. The innovation also creates possibilities for other breakthroughs in nanophotonics, which is the study of light-matter interaction at the nanometer scale. By bridging nanophotonics, nanochemistry and nanophysics, the research team discovered how to manipulate and analyze nanoparticles in ways that, before now, were beyond the reach of science.