Methods of blood-based therapies having a microfluidic membraneless exchange device

• US 8,021,318 B2
• Filed: 11/09/2010
• Issued: 09/20/2011
• Est. Priority Date: 03/14/2003
• Status: Expired due to Fees

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Shapley, Nina C., Tang, Zhongliang, West, Alan C., Leonard, Edward F.
• Primary Examiner(s): KIM, SUN U
• Application Number:
  US12/942,519
• Publication Number:
  US 20110056884A1
• Time in Patent Office: 315 Days
• Field of Search: 210/200, 210/201, 210/252, 210/258, 210/321.6, 210/456, 210/645, 210/646, 210/642, 210/643, 210/767, 210/805, 210/806, 422/100, 422/101, 422/104, 604/4.01, 604/5.01, 604/5.04, 604/6.09, 604/6.11, 604/6.16
• US Class Current: 604/5.04
• 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 1/1696 with dialysate regeneration
• CPC Class Codes: A61M 1/32 Oxygenators without membranes
• CPC Class Codes: A61M 1/3482 by filtrating the filtrate using another cross-flow filter, e.g. a membrane filter
• CPC Class Codes: A61M 1/3621 Extra-corporeal blood circuits single-needle circuits A61M1/30
• CPC Class Codes: A61M 2206/11 Laminar flow
• CPC Class Codes: B01D 11/04 of solutions which are liquid
• CPC Class Codes: B01D 11/0496 by extraction in microfluidic devices
• CPC Class Codes: B01D 61/243 Dialysis
• CPC Class Codes: B01D 61/244 comprising multiple dialysis steps
• CPC Class Codes: B01D 61/28 Apparatus therefor
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: G01N 2001/4016 being a selective membrane, e.g. dialysis or osmosis
• CPC Class Codes: Y10T 436/255 including use of a solid sorbent, semipermeable membrane, or liquid extraction

Abstract

The present invention is directed to devices, systems and methods for removing undesirable materials from a sample fluid by contact with a second fluid. The sample fluid flows as a thin layer adjacent to, or between, concurrently flowing layers of the second fluid, without an intervening membrane. In various embodiments, a secondary separator is used to restrict the removal of desirable substances and effect the removal of undesirable substances from blood. The invention is useful in a variety of situations where a sample fluid is to be purified via a diffusion mechanism against an extractor fluid. Moreover, the invention may be used for the removal of components from a sample fluid that vary in size. When blood is the sample fluid, for example, this may include the removal of ‘small’ molecules, ‘middle’ molecules, macromolecules, macromolecular aggregates, and cells, from the blood sample to the extractor fluid.

Claims

1. A method of performing a blood treatment on a patient, the method comprising:

attaching blood lines of a blood tubing set to a microfluidic channel;

attaching a membrane-based filter device to the microfluidic channel so as to define a recirculating flowpath uninterrupted by a membrane;

at a treatment time;

attaching a source of dialysate to the membrane-based filter device such that the dialysate flows on one side of a membrane of the filter device;

permitting toxins and water to pass from the microfluidic channel through the membrane of the filter device into the dialysate flow; and

returning components of the patient'"'"'s blood passing in the recirculating flowpath back to the patient'"'"'s blood; and

after the treatment time, disconnecting the source of dialysate while leaving the blood lines attached to the microfluidic channel.

2. The method of claim 1, further comprising, at a second treatment time after the disconnecting, repeating the attaching a source of dialysate, the permitting, and the returning.

3. The method of claim 2, further comprising, after the disconnecting and before the repeating, flowing blood and fluid together in the microfluidic channel.

4. The method of claim 1, wherein said permitting includes simultaneously flowing blood from the patient and fluid from the membrane-based filter device together in the microfluidic channel.

5. The method of claim 4, wherein the simultaneously flowing is such that the toxins and water move from the blood flow into the fluid from the membrane-based filter device without passing through any membrane.

6. The method of claim 1, wherein said components of the patient'"'"'s blood include blood proteins.

7. A method of performing a blood treatment on a patient, the method comprising:

co-flowing blood from the patient and recirculating fluid from a membrane-based filter device through a microfluidic channel such that toxins, water, and blood components are transferred from the blood flow into the recirculating fluid flow without passing through a membrane, the recirculating fluid flow with the toxins, water, and blood components exiting the microfluidic channel at an outlet thereof and returning to the membrane-based filter device;

at a treatment time;

connecting the membrane-based filter device to a source of dialysate; and

flowing the dialysate from the source along a side of a membrane in the membrane-based filter device such that toxins and water in the recirculating fluid flow move across the membrane into the dialysate flow; and

after the treatment time, disconnecting the membrane-based filter device from the source of dialysate.

8. The method of claim 7, wherein the co-flowing blood and recirculating fluid and the flowing the dialysate occur at a same time.

9. The method of claim 7, further comprising, after the disconnecting:

continuing to co-flow the blood and the recirculating fluid through the microfluidic channel.

10. The method of claim 7, wherein the blood components in the recirculating fluid flow exiting the microfluidic channel are returned to the microfluidic channel.

11. The method of claim 10, wherein the co-flowing blood and recirculating fluid is such that the blood components in the exiting recirculating fluid flow are returned to the flowing blood.

12. The method of claim 7, wherein the blood components include albumin.

13. The method of claim 7, wherein the recirculating fluid exiting the microfluidic channel flows through the membrane-based filter device on an opposite side of the membrane and is returned to the microfluidic channel to co-flow with the blood therein.

14. A method of performing a blood treatment on a patient, the method comprising:

flowing blood from the patient and recirculating fluid from a secondary processing device together along a microfluidic channel in a primary processing device such that toxins, water, and blood components are removed from the blood flow without passing through a membrane,

conveying fluid with the removed toxins, water, and blood components therein from an outlet of the primary processing device to an upstream inlet of the primary processing device via a flowpath through the secondary processing device; and

periodically using the secondary processing device to eliminate water and toxins from the fluid in the flowpath through the secondary processing device.

15. The method of claim 14, wherein the removed blood components at the outlet of the primary processing device are returned to the flowing blood in the microfluidic channel.

16. The method of claim 14, wherein:

the secondary processing device is a membrane-based filter device; and

water and toxins are eliminated from the fluid flowing through the filter device by passing the water and toxins across a membrane into a dialysate flow.

17. The method of claim 14, wherein the periodically using the secondary processing device includes:

connecting the secondary processing device to a source of dialysate; and

flowing the dialysate from the source along a side of a membrane in the secondary processing device such that the toxins and water move across the membrane into the dialysate flow while blood components are retained in the fluid flowing on an opposite side of the membrane.

18. The method of claim 14, wherein when the secondary processing device is not used to eliminate water and toxins, the secondary processing device is not connected to a source of dialysate.