Fabrication of linear colloidal structures for microfluidic applications

In this letter, an optical microfabrication and actuation method for the creation of microfluidic structures is described. In this approach, an optical trap is used to position and polymerize colloidal microspheres into linear structures to create particle or cell directing devices within microfluidic channel networks. To demonstrate the utility of these structures, two microscale particulate valves are shown, a passive design that restricts particulate flow in one direction and another design that directs particulate flow to one of two exit channels. (C) 2002 American Institute of Physics.