Nano-device Research: Playing with Legos for Science’s Sake
|Physicist German Drazer drops a ball bearing into a Lego pegboard. Courtesy of Will Kirk, Johns Hopkins University|
Researchers at Johns Hopkins University have developed an unorthodox method to study the behavior of microscopic nano-particles — by playing with Legos. The team, led by physicists Joelle Frechette and German Drazer, built a grid out of round Lego blocks and immersed it in liquid glycerin to observe the paths of ball bearings they dropped into the construction. Though Lego blocks are many times larger than a nano-device, particles passing through the grid behave fundamentally the same way, the researchers said.
By increasing the scale of the experiment from nano to Lego size, researchers are able to better visualize, describe and ultimately predict the behavior of the particles that normally are far too small to see. Many designs for nano-devices require the sorting of microscopic particles, and ball bearings immersed in glycerin behave much the same way as nano-particles in microfluidic arrays. By determining the likely paths that different sized bearings take on the Lego board, the researchers can predict the paths nanoparticles of different-sizes, charges or textures in the microfluidic arrays.
The team recorded the paths of ball bearings descending through the Lego obstacles and found that the smaller bearings zigzagged randomly through the grid, while the larger bearings followed more deterministic straight lines. The team’s complete results were published in the August 14 issue of Physical Review Letters.