Multi-channel microfluidic system design with balanced fluid flow distribution

A microfluidic fluid circuit comprising:

• an inlet;
• an outlet;
• and
• a plurality of flow paths that branch from the inlet, each providing a fluid connection between the inlet and the outlet;
• wherein at least a portion of each said flow path comprises a microchannel, and wherein each flow path is configured to produce a predetermined pressure drop for fluid flowing through the flow path at a predetermined flow rate, and wherein the resistance of each said flow path to fluid flow has been selected to produce flow rates of fluid through the flow paths in predetermined ratio with respect to other flow paths under wetted fluid circuit conditions.

A microfluidic circuit comprising:

• an inlet;
• an outlet;
• and
• a flow path between said inlet and said outlet, said flow path comprising a well structure in fluid communication between said inlet and said outlet, said well structure comprising:
• a well defined by a wall;
• a first exit channel that intersects the well via a first juncture with the wall;
• and
• a second exit channel that intersects the well via a second juncture with the wall;
• wherein the first and second junctures are displaced from each other along the wall to receive fluid from different portions of the well, each of the first and second junctures comprising an abrupt narrowing that forms a passive fluid flow barrier tending to restrict advancement of fluid from the well into the exit channel.

A microfluidic circuit comprising:

• an inlet;
• an outlet;
• and
• a flow path between said inlet and said outlet, said flow path comprising a well structure in fluid communication between said inlet and said outlet, said well structure comprising:
• a well defined by a wall;
• a first exit channel that intersects the well via a first juncture with the wall;
• and
• a first flow divider positioned within the well to separate fluid entering the well into first and second streams, at least one of which is oriented to direct fluid proximate the wall toward the first juncture.

A microfluidic circuit comprising:

• an inlet;
• an outlet;
• and
• a flow path between said inlet and said outlet, said flow path comprising a well structure in fluid communication between said inlet and said outlet, said well structure comprising:
• a well defined by a wall and having an inlet end and an outlet end;
• and
• a first exit channel that intersects the well via a first juncture with the wall at said outlet end;
• wherein the cross sectional area of said well increases gradually from said inlet end to the central region of said well, and decreases abruptly from the central region of said well to said outlet end, to give said well a generally pear-shaped configuration.

A microfluidic circuit comprising:

• an inlet;
• and
• at least two flow paths that branch from the inlet, each flow path comprising:
• a fluid handling structure;
• a filling portion adapted to receive fluid from the inlet and deliver fluid to the fluid handling structure;
• and
• a draining portion adapted to receive fluid from the fluid handling structure;
• wherein each flow path has a resistance to fluid flow that has been selected to produce flow rates of fluid through the flow paths in predetermined ratio with respect to other flow paths under wetted fluid circuit conditions.

A microfluidic circuit comprising:

• an inlet,
• a main distribution channel adapted to receive fluid from said inlet;
• and
• a plurality of entrance channels branching off said main distribution channel at multiple locations to deliver fluid to a plurality of flow paths, said entrance channels having cross-sectional areas or shapes selected in relation to the cross-sectional area of said main distribution channel such that when said microfluidic circuit is nonwetted fluid flows preferentially into and fills said main distribution channel before flowing into said entrance channels, and wherein the resistance of each said flow path to fluid flow has been selected to produce flow rates of fluid through the flow paths in predetermined ratio with respect to other flow paths under wetted fluid circuit conditions.