Microfabricated diffusion-based chemical sensor

A channel cell system for detecting the presence of analyte particles in a sample stream also comprising larger particles comprising:

• a) a laminar flow channel;
• b) at least two inlet means in fluid connection with said laminar flow channel for respectively conducting into said laminar flow channel (1) an indicator stream and (2) said sample stream;
• c) wherein said laminar flow channel has a depth sufficiently small to allow laminar flow of said streams and a length sufficient to allow particles of said analyte to diffuse into said indicator stream to the substantial exclusion of said larger particles in said sample stream to form a detection area;
• and
• d) a v-groove channel in fluid connection with said laminar flow channel.

A channel cell system for detecting the presence of analyte particles in a sample stream also comprising larger particles comprising:

• a) a laminar flow channel;
• b) at least two inlet means in fluid connection with said laminar flow channel for respectively conducting into said laminar flow channel (1) an indicator stream and (2) said sample stream;
• c) wherein said laminar flow channel has a depth sufficiently small to allow laminar flow of said streams and a length sufficient to allow particles of said analyte to diffuse into said indicator stream to the substantial exclusion of said larger particles in said sample stream to form a detection area;
• and
• d) a sheath flow module in fluid connection with said laminar flow channel.

A channel cell system for detecting the presence of analyte particles in a sample stream also comprising larger particles comprising:

• a) a convoluted laminar flow channel;
• b) at least two inlet means in fluid connection with said laminar flow channel for respectively conducting into said laminar flow channel (1) an indicator stream and (2) said sample stream;
• c) wherein said laminar flow channel has a depth sufficiently small to allow laminar flow of said streams and a length sufficient to allow particles of said analyte to diffuse into said indicator stream to the substantial exclusion of said larger particles in said sample stream to form a detection area;
• d) outlet means for conducting said streams out of said laminar flow channel to form a single mixed stream.

A channel cell system for detecting the presence of analyte particles in a sample stream also comprising larger particles comprising:

• a) a laminar flow channel;
• b) at least two inlets in fluid connection with said laminar flow channel for respectively conducting into said laminar flow channel (1) an indicator stream and (2) said sample stream;
• c) wherein said laminar flow channel has a width greater than about 20 microns, a depth sufficiently small to allow laminar flow of said streams and a length sufficient to allow particles of said analyte to diffuse into said indicator stream to the substantial exclusion of said larger particles in said sample stream to form a detection area;
• d) an outlet for conducting said streams out of said laminar flow channel to form a single mixed stream;
• and
• e) an optical analyte detection area.

A channel cell system formed in a substrate plate for detecting by transmission the presence of analyte particles in a sample stream also comprising larger particles comprising:

• a) a laminar flow channel;
• b) at least two inlet means in fluid connection with said laminar flow channel for respectively conducting into said laminar flow channel (1) an indicator stream and (2) said sample stream;
• c) wherein said laminar flow channel has a depth sufficiently small to allow laminar flow of said streams and a length sufficient to allow particles of said analyte to diffuse into said indicator stream to the substantial exclusion of said larger particles in said sample stream to form a detection area;
• d) outlet means for conducting said streams out of said laminar flow channel to form a single mixed stream;
• e) at least one analyte detection area between said inlet means and said outlet means;
• f) optically transparent plates sealed to both sides of said substrate plate;
• and
• g) wherein said analyte detection area lies between said transparent plates in a space cut through the width of said substrate plate.