Microfluidic manifold for shear sensitive fluids

• US 9,784,396 B2
• Filed: 02/17/2015
• Issued: 10/10/2017
• Est. Priority Date: 02/17/2014
• Status: Active Grant

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Charest, Joseph L., Borenstein, Jeffrey T., Epshteyn, Alla, Harjes, Daniel I., DiBiasio, Christopher, Kolachalama, Vijaya
• Primary Examiner(s): Schneider, Craig
• Assistant Examiner(s): Hicks, Angelisa L
• Application Number:
  US14/624,247
• Publication Number:
  US 20150233512A1
• Time in Patent Office: 966 Days
• Field of Search: 137561 A, 137833
• CPC Class Codes: A61M 1/14 Dialysis systems; Artificial kidneys; Blood oxygenators semi-permeable membranes characterised by the material, manufacturing processes therefor B01D71/00 ; Reciprocating systems for treatment of body fluids, e.g. single needle systems for hemofiltration or pheresis
• CPC Class Codes: A61M 1/1627 Dialyser of the inside perfusion type, i.e. blood flow inside hollow membrane fibres or tubes
• CPC Class Codes: A61M 2205/0244 Micromachined materials, e.g. made from silicon wafers, microelectromechanical systems [MEMS] or comprising nanotechnology
• CPC Class Codes: A61M 2206/20 having means for promoting or enhancing the flow, actively or passively
• CPC Class Codes: A61M 2207/00 Methods of manufacture, assembly or production
• CPC Class Codes: B01D 2325/028 Microfluidic pore structures
• CPC Class Codes: B01D 63/088 Microfluidic devices comprising semi-permeable flat membranes
• CPC Class Codes: B29C 2045/0058 removing material
• CPC Class Codes: B29C 2045/0077 removing burrs or flashes in general B29C37/02
• CPC Class Codes: B29C 45/0055 Shaping
• CPC Class Codes: B29C 45/0062 Joined by injection moulding
• CPC Class Codes: F16L 41/02 Branch units, e.g. made in one piece, welded, riveted

Abstract

A microfluidic device is provided. A manifold having a first channel, a second channel, and a third channel configured to transport blood can be coupled to a substrate defining an artificial vasculature. The first channel can be configured to carry blood in a first direction. Each of the second and third channels can couple to the first channel at a first junction and can be configured to receive blood from the first channel. The second channel can be configured to carry blood in a second direction away from the first direction. The third channel can be configured to carry blood in a third direction away from the second direction. The first, second, and third channels can be non-coplanar.

Claims

1. A microfluidic device comprising:

a manifold having a first manifold channel, a second manifold channel, and a third manifold channel, coupled to a substrate defining an artificial vasculature, wherein;

the first manifold channel is configured to carry blood in a first direction;

each of the second and third manifold channels couples to the first manifold channel at a first junction and is configured to receive blood from the first manifold channel such that a total blood flow rate through the second and third manifold channels is substantially the same as a blood flow rate through the first manifold channel;

the second manifold channel is configured to carry blood in a second direction away from the first direction;

the third manifold channel is configured to carry blood in a third direction away from the first direction; and

the first, second, and third manifold channels are not arranged to all carry fluid in directions that lie within a common plane, wherein;

at least one of the first manifold channel, the second manifold channel and the third manifold channel further comprises a transition region,

the cross-sectional area of the at least one manifold channel upstream from the transition region such that fluid flowing through the at least one manifold channel downstream from the transition region experiences a higher shear rate than fluid flowing through the at least one manifold channel upstream from the transition region is larger than the cross-sectional area of the at least one manifold channel downstream from the transition region and

the transition region comprises sidewalls that narrow at least one manifold according to one of a Hicks-Henne bump function, a non-uniform rational basis spline, a cubic spline, a T spline, a point cloud, and a polynomial function.

2. The microfluidic device of claim 1, wherein walls of the junction are defined by one of a Hicks-Henne bump function, a non-uniform rational basis spline, a cubic spline, a T spline, a point cloud, and a polynomial function.

3. The microfluidic device of claim 1, wherein:

the first manifold channel is further configured to carry blood at a first wall shear rate;

the second manifold channel is further configured to carry blood at a second wall shear rate, lower than the first wall shear rate; and

the third manifold channel is further configured to carry blood at a third wall shear rate, lower than the first wall shear rate.

4. The microfluidic device of claim 3, wherein the first junction is configured to ensure that a wall shear rate gradient through the junction is maintained below a threshold selected to maintain blood health.

5. The microfluidic device of claim 4, wherein the threshold is about 0.0006 inverse seconds per micron.

6. The microfluidic device of claim 3, wherein the first manifold channel is configured to transport blood at a wall shear rate in the range of about 4500 inverse seconds to about 10,000 inverse seconds.

7. The microfluidic device of claim 3, wherein at least one of the second manifold channel and the third manifold channel is configured to transport blood at a wall shear rate in the range of about 100 inverse seconds to about 800 inverse seconds.

8. The microfluidic device of claim 3, wherein the first wall shear rate is selected to create a driving force sufficient to dislodge blood clots in the manifold.

9. The microfluidic device of claim 1, wherein the transition region is configured to ensure that a wall shear rate gradient through the manifold channel is maintained below about 0.0006 inverse seconds per micron.

10. The microfluidic device of claim 1, further comprising fourth and fifth manifold channels, wherein:

each of the fourth and fifth manifold channels couples to the second manifold channel at a second junction and is configured to receive blood from the second manifold channel such that a total blood flow rate through the fourth and fifth manifold channels is substantially the same as a blood flow rate through the second manifold channel;

the fourth manifold channel is configured to carry blood in a fourth direction away from the second direction;

the fifth manifold channel is configured to carry blood in a fifth direction away from the second direction; and

the second, fourth, and fifth manifold channels are not arranged to all carry fluid in directions that lie within a common plane.

11. The microfluidic device of claim 10, wherein:

the fourth manifold channel is further configured to carry blood at a fourth wall shear rate, lower than the second wall shear rate; and

the fifth manifold channel is further configured to carry blood at a fifth wall shear rate, lower than the second wall shear rate.

12. The microfluidic device of claim 1, wherein the transition region is configured to change the wall shear rate experienced by blood transported through the at least one channel such that the wall shear rate experienced by blood upstream from the transition region is lower than a wall shear rate experienced by blood downstream from the transition region.

13. The microfluidic device of claim 12, wherein a length of the transition region is selected to achieve a desired wall shear rate gradient in the transition region.

14. The microfluidic device of claim 13, wherein the length of the transition region is inversely proportional to the wall shear rate gradient in the transition region.

15. The microfluidic device of claim 1, wherein the manifold further comprises sixth and seventh manifold channels that converge at a third junction to form an eighth manifold channel, such that a blood flow rate through the eighth channel is substantially the same as a total blood flow rate through the sixth and seventh manifold channels, and wherein:

the sixth channel is configured to transport blood at a sixth wall shear rate;

the seventh channel is configured to transport blood at a seventh wall shear rate; and

the eighth channel is configured to transport blood at an eighth wall shear rate, lower than both the sixth and seventh wall shear rates.