incorporates valvmg modules in accordance with the present invention.

Figure 6 schematically illustrates the operation of the valving modules in the channel illustrated in Figure 5A.

DETAILED DESCRIPTION OF THE INVENTION The present invention is generally directed to microfluidic structures, and particularly, channel structures that include an integrated valve module. As used herein, the phrase "valve module" refers to a series of interconnected channels that, when operated in an appropriate manner, functions to arrest flow of fluids or other materials in at least one of the interconnected channels in the network. The valve modules employed in the methods and systems of the present invention employ no mechanical or moving parts within the channel structure, and operate primarily by presenting a force at an end of a channel segment that ismay be practiced within the scope of the appended claims.

Claims

What is claimed is: 1. A method of controlling material flow in a microscale channel, comprising: providing a first channel segment having first and second ends, a second channel segment communicating with the first channel segment at a first fluid junction, the first fluid junction being disposed between the first and second ends of the first channel segment, and a third channel segment communicating with the first channel segment at a second fluid junction, the second fluid junction being disposed between the first fluid junction and the second end of the first channel segment; applying a differential driving force between the first and second ends of the first channel segment; and selectively applying a second differential driving force through