Novel Method of Creating Micro-Structures for Micro-Fluidic Applications

Researchers at Arizona State University have discovered a method of creating microscopic structures of various types of colloidal particles (including biological structures) using externally applied magnetic fields. The combination of induced structure and the dynamic reversible nature of the system is novel and engenders many applications, especially in the area of micro-fluidics and diagnostic microchips.Upon application of an external magnetic field using the proper parameters, a supraparticle structure can be formed with individual collections of paramagnetic particles. Moreover, these structures can be actively manipulated. Patterning can be actively controlled from the macroscopic level. In fact, dynamic patterning also occurs even when fluid is flowing in a microchannel. There is great utility in harnessing this phenomenon within microdevices for micropatterning and dynamic optics, and for static and fluidic small liquid volume applications. The system has the following unique properties: 1. within microchannels, paramagnetic particles respond rapidly and reversibly; 2. microchip geometry has an influence on the structures formed; 3. under electroosmotic and pressure pumping, the paramagnetic particles retain the patterns induced by the local orienting field; 4. these are truly dynamic structures in ultrasmall volumes (nanoliter to picoliter). Based on these unique properties, the potential exists for developing a variety of new types of microchips. A few of the more prominent applications would be as follows:1. Dynamic Masks for Photolithography and Photopolymerization: The orientation of the structures and the ability to form parallel lines and other morphologies can lead to a unique method for creating inexpensive, and dynamic photon masks2. Sub-Cellular Manipulator: Microchips to identify and separate cells represent a new type of cell manipulation microchip that could potentially benefit researchers and advance diagnostic methodsOther applications of this discovery are either too numerous to mention here or have yet to be thought of.