METHOD AND SYSTEM FOR PRE-PROGRAMMED SELF-POWER MICROFLUIDIC CIRCUITS

• US 20140332098A1
• Filed: 08/30/2012
• Published: 11/13/2014
• Est. Priority Date: 08/30/2011
• Status: Active Grant

• Current Assignee: McGill University
• Original Assignee: McGill University
• Inventors: Juncker, David, Safavieh, Hosseinali
• Granted Patent: US 9,822,890 B2
• Time in Patent Office: Days
• US Class Current: 137/511
• CPC Class Codes: B01L 2200/0621 Control of the sequence of chambers filled or emptied
• CPC Class Codes: B01L 2200/16 Reagents, handling or storing thereof
• CPC Class Codes: B01L 2300/044 pierceable, e.g. films, membranes
• CPC Class Codes: B01L 2300/048 enabling gas exchange, e.g. vents
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0867 Multiple inlets and one sample wells, e.g. mixing, dilution
• CPC Class Codes: B01L 2300/087 Multiple sequential chambers
• CPC Class Codes: B01L 2300/0883 Serpentine channels
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0688 surface tension valves, capillary stop, capillary break
• CPC Class Codes: B01L 2400/0694 vents used to stop and induce flow, backpressure valves
• CPC Class Codes: B01L 2400/086 using baffles or other fixed flow obstructions
• CPC Class Codes: B01L 3/50273 characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: B01L 3/502746 characterised by the means for controlling flow resistance, e.g. flow controllers, baffles B01L3/502738 takes precedence
• CPC Class Codes: F16K 15/18 with actuating mechanism; Combined check valves and actuated valves
• CPC Class Codes: Y10T 137/7837 Direct response valves [i.e., check valve type]

Abstract

A major challenge for the general use of “lab-on-a-chip” (LOAC) systems and point-of-care (POC) devices has been the generally complex and need for sophisticated peripheral equipment, such that it is more difficult than anticipated to implement low cost, robust and portable LOAC/POC solutions. It would be beneficial for chemical, medical, healthcare, and environmental applications to provide designs for inexpensive LOAC/POC solutions compatible with miniaturization and mass production, and are potentially portable, using compact possibly hand-held instruments, using reusable or disposable detectors. Embodiments of the invention address improved circuit elements for self-powered self-regulating microfluidic circuits including programmable retention valves, programmable trigger valves, enhanced capillary pumps, and flow resonators. Additionally embodiments of the invention allow for the flow direction within a microfluidic circuit to be reversed as well as for retention of reagents prior to sale or deployment of the microfluidic circuit for eased user use.

Claims

1. A device comprising:

a first microfluidic channel having a first predetermined width, a first predetermined depth and at least a sidewall;

a second microfluidic channel having a second predetermined width and a second predetermined depth, the second microfluidic channel disposed with a first end at a first predetermined offset from the first microfluidic channel and having an axis orientated at a first predetermined angle relative to the sidewall of the first microfluidic channel;

a third microfluidic channel having a third predetermined width less than that of the second predetermined width and a third predetermined depth less than that of the second predetermined depth, the third microfluidic device disposed between the first end of the second microfluidic channel and the sidewall of the first microfluidic channel and having an axis orientated at a second predetermined angle relative to an axis of the first microfluidic channel;

wherein

a first fluid introduced into the second microfluidic channel will fill the second and third microfluidic channels but does not flow into the first microfluidic channel until a second fluid is present within the first microfluidic channel.

2. The method according to claim 1 further comprising:

a cover over the first, second, and third microfluidic channels, the cover at least one of;

comprising a recess to be situated above the first, second, and third microfluidic channels such that a sidewall of the recess acts to extend a sidewall of the first microfluidic channel such that the third microfluidic circuit opens essentially into a planar surface; and

providing a hydrophobic coating on a predetermined region of the cover adjacent the first, second, and third microfluidic channels, the predetermined region comprising at least where the third microfluidic channel intersects the first microfluidic channel.

3. The method according to claim 1 wherein,

the aspect ratio of each of the first, second, and third microfluidic channels is less than at least one of 2:

1;

3;

1, and 5;

1.

4. A device comprising:

a first microfluidic channel having a first predetermined width, a first predetermined depth, a first end coupled to a first predetermined portion of a microfluidic circuit, and a second distal end coupled to a first end of a third microfluidic channel;

a second microfluidic channel having a second predetermined width over a predetermined section of the second microfluidic channel, a second predetermined depth, a first end coupled to a second end of the third microfluidic channel, and a second distal end coupled to a second predetermined portion of the microfluidic circuit;

the third microfluidic channel having a third predetermined width less than that of the first predetermined width, a third predetermined depth, and disposed between the first and second microfluidic channels;

wherein

the dimensions of the second microfluidic channel are selected to establish a predetermined retention pressure for the combination of first, second, and third microfluidic channels such that a fluid coupled into the first microfluidic channel is coupled to the second and third microfluidic channels and is retained until the pressure within the first microfluidic channel arising from the first predetermined portion of a microfluidic circuit exceeds the predetermined retention pressure and the fluid is drained from the first, second, and third microfluidic channels without being pinned within the third microfluidic channel.

5. A device comprising:

an inlet coupled to a first corner of a first predetermined region of a microfluidic element;

an outlet coupled to a second corner of the first predetermined region of the microfluidic element;

the first predetermined region formed within a microfluidic element comprising a recess having a first predetermined depth and comprising a plurality of posts disposed in a plurality of rows of first predetermined spacing between adjacent rows, second predetermined spacing between adjacent posts within a row, and having a first predetermined angle with respect to an axis of the inlet, each post of the plurality of posts having predetermined dimensions such that a first channel of first predetermined width is formed between adjacent posts within a row and a second channel of second predetermined width is formed between adjacent rows.

6. The device according to claim 5 wherein,

first and second predetermined spacings and predetermined dimensions are such that fluid flow from the inlet to the outlet is primarily along the gaps between adjacent rows of posts rather then between the gaps of adjacent posts within each row.

7. The device according to claim 5 wherein,

the plurality of posts are disposed so that between the plurality of posts and the sidewalls of the recess are open effective channels around the periphery of the recess, each channel having a predetermined width determined in dependence upon establishing predetermined pressure differentials between fluid within each channel and fluid within the region comprising the plurality of posts.

8. The device according to claim 6 wherein,

a first pressure differential between fluid within adjacent rows is higher than a second pressure differential between fluid within a first channel combination leading from the inlet to the outlet and the second pressure differential is higher than a third pressure differential between fluid within a second channel combination leading from the inlet to the outlet, the second channel combination not including channels within the first channel combination.

9. A device comprising:

a trigger valve, the trigger valve coupling between a first microfluidic channel and a second microfluidic channel and retaining a first fluid within the first microfluidic channel after the trigger valve until a second fluid fills the second microfluidic channel;

a capillary pump coupled to the second microfluidic channel causing the second fluid to trigger the trigger valve linking the first and second microfluidic channels and reversing the flow of the first fluid within the first microfluidic channel such that the first fluid within the first microfluidic channel after the trigger valve now flows back to the trigger valve and into the second microfluidic channel.

10. The device according to claim 9 wherein,

the trigger valve comprises:

a first trigger channel having a first predetermined width, a first predetermined depth and coupled to the first microfluidic channel, having an axis orientated at a first predetermined angle relative to the sidewall of the first microfluidic channel, and a first end coupled to the first microfluidic channel;

a second trigger channel having a second predetermined width less than that of the first predetermined width and a second predetermined depth less than that of the first predetermined depth, the second trigger channel disposed between a second distal end of the first trigger channel and a sidewall of the second microfluidic channel and having an axis orientated at a second predetermined angle relative to an axis of the second microfluidic channel.

11. The device according to claim 9 further comprising;

at least one retention channel of a plurality of retention channels, each retention channel coupled at a first end to the first microfluidic channel and at a second distal end to a vent via a retention valve having a predetermined burst pressure, wherein

the flow reversal within the microfluidic channel and resulting pressure within the first microfluidic channel through the action of the capillary pump exceeds the predetermined burst pressure thereby causing the retention valve to open and the retention channel to be drained into the first microfluidic channel.