Smallest Pumps of the Size of Blood Cells (2010.5.17)
Amicrofluidic chip that can diagnose the warning signs of stroke (or cerebrovascular accidents) with only one percent of one drop of blood or medical devices that may be able to treat something as tiny as blood cells were previously just subjects for science fiction. But a recent study done by a POSTECH-Michigan University (USA) research team broke open the possibility to turn such ideas into reality. The study was selected as the Featured Paper on the May 17th edition of Nature Nanotechnology Online, a respected journal in the field of nanoscience.
Dr. Sanghyun Lee, postdoctoral researcher at POSTECH’s Department of Mechanical Engineering, and Dr. Alan Hunt at the University of Michigan jointly discovered a new property of electric insulators. Even though insulators inherently resist the flow of electrical currents, the researchers discovered that the insulators act like a normal semi-conductor and transmit even a very low voltage if reduced to nano-size.
Based on this new discovery, and through close examination on the basic principles, the Lee-Hunt team developed a very small electrokinetic pump of the size of blood cells. Furthermore, they successfully devised a nano-liquid-glass electrode, which can be used with nano-devices.
Owing to the advantage of being made of glass, which allows the electrode to be purely independent of electrical transmission, it does not need both conductors and nonconductors to be simultaneously connected. The electorde can then be applied to the development of nano-sized semiconductors or ‘lab-on-a-chips’, a type of high technology biochip that can be used to diagnose medical disorders with only one percent of one drop of blood.
Micro-machining technology enables several devices for chemical analysis to become integrated into one coin-sized chip, which is capable of performing a great number of functions of various laboratory equipments. More specifically, the chip can process substances and ores and even handle their separation, and not only is it swift in diagnosis, but it also possesses a very appealing advantage of being portable.
In addition to lab-on-a-chips, the recent development is expected to be applied not only to nano-sized semiconductors, which were difficult to commercialize until now due to its electrical conductivity, but also to nano-sized medical devices that can treat single cells. Moreover, the recent discovery has gathered attention of the scientific world because it can be applied directly to existing chips, thanks to the liquid-assisted three-dimensional femtosecond (fs)-laser nanomachining technology developed by Dr. Hunt’s research team. This particular aspect belongs to a field of fs-laser processing, which has a very short pulse width in the level of femtoseconds (1 divided by 1000 trillion seconds).
“Until now, electrokinetic sensors needed to integrate conductors and non-conductors simultaneously, which made it very difficult to develop devices at micro size,” commented Dr. Lee. “Therefore, our recent development is significant in the sense that it can be of great help to the semi-conductor industry, where miniaturization is difficult to achieve.”