January 20, 2012 — Purdue University researchers have created microtweezers for the manufacture of tiny structures in micro electro mechanical systems (MEMS), printing coatings on advanced sensors, and live stem cell sphere manipulation.
The variety of miniature structures in MEMS could be expanded using this microtweezer manufacturing technology, which assembles components like microscopic Lego pieces moved individually into place, said Cagri Savran, an associate professor of mechanical engineering at Purdue University. The microtweezers are compact and user-friendly, he added, and the team has demonstrated them by assembling 40um-diameter polystyrene spheres into three-dimensional shapes (at left below). It can also place tiny particles on the tip of a microcantilever (at right below).
 |
| Figure 1. Microtweezers constructing tiny structures at Purdue University. SOURCE: Birck Nanotechnology Center. |
The new tool comprises a thimble knob from a standard micrometer, a two-pronged tweezer made from silicon, and a graphite interface that converts the turning motion of the thimble knob into a pulling-and-pushing action to open and close the tweezer prongs. No electrical power sources are needed. The new microtweezers are designed to be attached easily to translation stages and can be easily detached from a platform and brought to another lab while still holding a micro-size object for study, Savran said.
The two-pronged tweezer is micromachined in a cleanroom with the same techniques used to create semiconductors. The design’s one-piece "compliant structure," which is springy like a bobby pin or a paperclip, replaces the more complex hinges and other components of common microtweezers.
 |
| Figure 2. Purdue researchers’ microtweezers. SOURCE: Birck Nanotechnology Center. |
"We currently are working to weigh single micro particles, individually selected among many others, which is important because precise measurements of an object’s mass reveal key traits, making it possible to identify composition and other characteristics," Savran said. That work is a collaboration with the research group of Timothy Ratliff, the Robert Wallace Miller Director of Purdue’s Center for Cancer Research.
The microtweezers also could facilitate the precision printing of chemical or protein dots onto microcantilevers to functionalize them for specific purposes. Microprinting a sequence of precisely placed dots of different chemicals on each cantilever, rather than coating it in one chemical, could functionalize a device to detect several substances at once with a smaller sample size.
The research was based at the Birck Nanotechnology Center in Purdue’s Discovery Park. Purdue has filed for a provisional patent on the design.
The research is described in the Journal of Microelectromechanical Systems (JMEMS) by Savran, mechanical engineering graduate students Bin-Da Chan and Farrukh Mateen, electrical and computer engineering graduate student Chun-Li Chang, and biomedical engineering doctoral student Kutay Icoz. Access the journal here: http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=84
Courtesy of Emil Venere at Purdue University.
Research contact: Cagri A. Savran, 765 494-8601, [email protected].
Recently, National Institute of Standards and Technology (NIST) and the University of Virginia (UVA) have demonstrated that electron microscope beams can be used to move around nanoscale objects, raising the possibility of positioning and assembling nanoelectronics. Learn more: Electron beam could assemble nanoscale objects