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US 6,615,856 B2Granted
Remote valving for microfluidic flow control
AssigneeBioMicro Systems, Inc.
InventorsMichael R. McNeely, Mark K. Spute
Life of this patent
Estimating the term…
Abstract
A method of controlling fluid flow within a microfluidic circuit using external valves and pumps connected to the circuit is disclosed. The external valves and pumps, which are not a part of the microfluidic substrate, control fluid pumping pressure and the displacement of air out of the fluid circuit as fluid enters into the circuit. If a valve is closed, air cannot be displaced out of circuit, which creates a pneumatic barrier that prevents fluid from advancing within the circuit (under normal operating pressures). Applications of this method of fluid control are explained.
Claims54
A method of controlling fluid flow within a microfluidic circuit comprising:
- (a) providing a micro fluidic circuit comprising an inlet through which fluid is introduced into the circuit, at least one microchannel for fluid flow in fluid communication with said inlet, at least one upstream air duct in communication with said at least one microchannel at an upstream connection point, and at least one downstream air duct in communication with said at least one microchannel at a downstream connection point, wherein said at least one microchannel is initially filled with air that is displaced by advancing fluid, and wherein said at least one upstream air duct and said at least one downstream air duct are configured to prevent fluid from entering the air ducts;
- (b) introducing a fluid into the inlet;
- and
- (c) controlling the opening and closing of the air ducts, thereby releasing and generating a pneumatic pressure barrier proximate to and downstream of at least one said connection point to control the flow of fluid in said at least one microchannel.
1 more element
A method of controlling fluid flow in a microfluidic circuit, comprising the steps of:
- (a) providing a microfluidic circuit comprising an inlet, at least one microchannel, and at least one air duct communicating with said at least one microchannel, wherein said microfluidic circuit is initially filled with air;
- (b) introducing fluid into said microfluidic circuit under pressure via said inlet;
- (c) causing fluid to advance in said microchannel upstream of one said air duct while permitting air downstream of the advancing fluid to flow out of said microchannel via said air duct;
- and
- (d) subsequently preventing the flow of air out of said microchannel via said air duct, thereby generating a pneumatic pressure barrier in said microchannel opposing advancement of fluid in said microchannel.
2 more elements
A microfluidic circuit comprising:
- a substrate having at least one channel for fluid flow and having at least one air duct connecting to said at least one channel at a first connection point, herein said at least one channel is initially filled with air that is displaced by advancing fluid;
- and
- at least one stopping point proximate to and downstream of said First connection point where the flow of fluid advancing in said at least one channel from upstream of said first connection point can be at least temporarily slopped by a controllable pneumatic pressure barrier;
- wherein said at least one air duct is configured to permit the escape of said air displaced by said advancing fluid from an air column within said channel while said fluid is upstream of said first connection, and wherein said at least one air duct is configured to prevent the escape of air from said air column when said fluid has advanced past said first connection point.
1 more element
A microfluidic circuit comprising:
- (a) a plurality of connected microchannels;
- (b) an inlet through which fluid is introduced into the circuit, said circuit being initially filled with air that is displaced by advancing fluid;
- and
- (c) a plurality of air ducts, each said air duct in communication with one of said microchannels at a connection point, wherein said air ducts are selectively opened or closed to control gas flow into and out of said microchannels to generate and release pneumatic barriers within said microchannels thereby controlling fluid flow within the circuit,
- wherein each said pneumatic barrier is generated at a stopping point proximate to and downstream of one connection point when said microchannel contains a closed air column downstream of said stopping point, and is released by opening of at least one air duct downstream of said connection point to permit the escape of air from said microchannel through said air duct.
2 more elements
A fluid handling system comprising:
- (a) a substrate having formed therein a microfluidic circuit comprising an inlet, at least one microchannel in fluid communication with said inlet, and at least one air duct communicating with said microchannel;
- (b) a fluid source connected to said inlet for introducing fluid into said microfluidic circuit, said microfluidic circuit being initially filled with air that is displaced as fluid enters said circuit;
- and
- (c) an external valve connected to said at least one air duet for regulating the flow of gases through said at least one air duct;
- wherein flow of gases out of said microchannel through said air duct weakens a pneumatic pressure barrier obstructing the flow of fluid in said at least one microchannel upstream of said air duct and flow of gases into said microchannel through said air duct strengthens a pneumatic pressure barrier obstructing the flow of fluid in said at least one microchannel upstream of said air duct.
2 more elements
A microfluidic device comprising:
- (a) a substrate;
- (b) a microfluidic fluid circuit formed in said substrate, the microfluidic circuit comprising:
- (1) an inlet;
- (2) at least one microchannel in fluid communication with said inlet, said microchannel being initially filled with air;
- (3) at least one air duct communicating with said microchannel at a first connection point and adapted to control the flow of fluid advancing in said microchannel by controlling a pneumatic pressure barrier located in said microchannel downstream of the advancing fluid, wherein fluid advancing in said at least one microchannel can be at least temporarily stopped by the controllable pneumatic pressure hairier at a stopping point, and wherein said at least one air duct is configured to prevent the escape of said air displaced by said advancing fluid from an air column within said microchannel while said fluid is upstream of said first connection point, and wherein said at least one air duct is configured to prevent the escape of air from said air column when said fluid has advanced past said first connection point;
- and
- (c) a sensor for detecting the position of a fluid within said microfluidic circuit.
4 more elements
Dependencies are inferred from the claim text.