Patent ID: 7214298

Claim:
A microfluidic system for processing a flow of biological material in a fluid, wherein said system comprises: (i) a substrate having an analysis unit microfabricated thereon, wherein said analysis unit comprises (a) a main channel in communication with a sample inlet, (b) a detection region downstream of the sample inlet, (c) a branch point discrimination region adjacent to and downstream of the detection region; and (d) at least two branch channels originating at the branch point discrimination region and in communication with the main channel; (ii) a detection apparatus for evaluating the biological material according to at least one characteristic as the material passes through the detection region; (iii) a processor configured to receive a signal from the detection apparatus and in response to the signal, actuate the flow control system to reverse the flow of fluid in a branch channel; and (iv) a flow control system, wherein said flow control system is responsive to the processor and is adapted to direct biological material into a selected branch channel and to reverse the direction of movement of biological material that has been directed into a selected branch channel.