Patent ID: 7422669

Claim:
A method of forming and dispensing minute volume segments of a material in a microfluidic device, said method comprising the steps of: providing a microfluidic device that includes a body having first, second, third, and fourth microchannels formed therein, said first, second, third, and fourth microchannels communicating at a first intersection and said first microchannel being connected to a source of a first material; providing a first focusing channel in said body having one end in fluid communication with a source of a focusing material and a second end in fluid communication with said first channel between said source of the first material and the first intersection; transporting a stream of the first material through said first channel toward the first intersection, said stream of first material having a width; transporting a stream of the focusing material from the first focusing channel into said first channel, such that the width of the stream of first material in said first channel is narrowed; and dispensing a volume segment of the narrowed first material stream into the fourth channel.