Microfabricated differential extraction device and method

A microfabricated extraction device for extracting desired particles from a sample stream containing said desired particles comprising:

• a. a sample stream inlet;
• b. an extraction stream inlet;
• c. an extraction channel having a depth less than about 100 micrometers joining with said sample stream inlet and said extraction stream inlet for receiving a sample stream from said sample stream inlet and an extraction stream from said extraction stream inlet, and forming parallel laminar flow therewith;
• d. a by-product stream outlet in fluid communication with said extraction channel for receiving a by-product stream comprising at least a portion of said sample stream from which desired particles have been extracted;
• and
• e. a product stream outlet in fluid communication with said extraction channel for receiving a product stream comprising at least a portion of said extraction stream and comprising desired particles extracted from said sample stream;
• said device being constructed and arranged such that said parallel laminar flow is preserved throughout said extraction channel.

An analytical system microfabricated on a silicon wafer comprising:

• a. extraction means for extracting desired particles of an analyte comprising:
• (1) a sample stream inlet;
• (2) an extraction stream inlet;
• (3) an extraction channel having an aspect ratio (w/d) less than 50 joining with said sample stream inlet and said extraction stream inlet for receiving a sample stream from said sample stream inlet and an extraction stream from said extraction stream inlet, and forming parallel laminar flow therewith;
• (4) a by-product stream outlet in fluid communication with said extraction channel for receiving a by-product stream comprising at least a portion of said sample stream from which at least a portion of said desired analyte particles have been extracted;
• and
• (5) a product stream outlet in fluid communication with said extraction channel for receiving a product stream comprising at least a portion of said extraction stream and comprising desired analyte particles extracted from said sample stream;
• (6) said extraction means being constructed and arranged such that said parallel laminar flow is preserved throughout said extraction channel;
• b. a diffusion-based mixing device for mixing said product stream with an indicator substance capable of interacting with said desired analyte particles so as to enable their detection;
• c. a detection chamber wherein the presence of said desired analyte particles may be detected.