Micro fluidic system and a method of attaching a membrane to a tube

• US 8,449,772 B2
• Filed: 08/22/2006
• Issued: 05/28/2013
• Est. Priority Date: 08/24/2005
• Status: Active Grant

• Current Assignee: Flowsion APS
• Original Assignee: Flowsion APS
• Inventors: Dirac, Holger, Rasmussen, Per Brandt, Briest, Arne
• Primary Examiner(s): Kim, John
• Application Number:
  US12/064,483
• Publication Number:
  US 20090218272A1
• Time in Patent Office: 2,471 Days
• Field of Search: 210/244, 210/321.6, 210/321.64, 210/321.78, 210/321.79, 210/321.8, 210/321.87, 210/321.88, 210/321.89, 210/500.21, 210/500.23, 210/500.26, 298/901
• US Class Current: 210/321.89
• CPC Class Codes: A61B 10/0045 Devices for taking samples of body liquids devices for taking blood samples A61B5/15
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61M 1/1678 intracorporal peritoneal dialysis A61M1/28
• CPC Class Codes: Y10T 29/49401 Fluid pattern dispersing device making, e.g., ink jet

Abstract

A micro fluidic system comprising at least one tube (1), a membrane (3) and at least one fitting member (4). The fitting member (4) is positioned around the membrane (3) and an end part (2) of the tube(s) (1), thereby fitting the membrane (3) to the end part(s) (2). The fitting member(s) (4) is/are made from a shrinkable material, and it/they is/are fitted tightly around the membrane (3) end part(s) (2). This is obtained by causing the shrinkable material to shrink, e.g. by heating the material, while the fitting member (4) is positioned around the membrane (3) and the end part(s) (2). It is an advantage that the fitting member (4) is made from a shrinkable material because this provides the possibility of fitting the membrane (3) tightly to the end part(s) (2) in an easy and cost effective manner. The micro fluidic system is very suitable for use in a probe, such as a dialysis probe. Also claimed is a method of manufacturing the micro fluidic system.

Claims

1. A micro fluidic system comprising:

a single multi-lumen tube defining two or more lumens substantially parallelly arranged side-by-side, the single multi-lumen tube defining a reduced portion;

a semi-permeable dialysis membrane positioned over the reduced portion of the single multi-lumen tube;

at least one fitting member positioned around the semi-permeable dialysis membrane and a portion of the single multi-lumen tube, thereby fitting the semi-permeable dialysis membrane to said portion of the single multi-lumen tube;

wherein the fitting member(s) is/are made from a shrinkable material, and wherein the fitting member(s) is/are fitted tightly around the semi-permeable dialysis membrane and the portion of the single multi-lumen tube where the membrane is fitted;

wherein a cavity is formed between the reduced portion of the single multi-lumen tube and the semi-permeable dialysis membrane.

2. The micro fluidic system according to claim 1, wherein at least two of the lumens are arranged at least substantially along a common axis and with their end parts facing each other.

3. The micro fluidic system according to claim 1, wherein the lumens are capillary tubes.

4. The micro fluidic system according to claim 3, wherein at least one of the capillary tubes is a glass capillary tube.

5. The micro fluidic system according to claim 3, wherein a transversal dimension for at least one of the capillary tube(s) is within the interval 0.5 μ

m to 500 μ

m.

6. The micro fluidic system according to claim 1, further comprising a substantially rigid hood positioned at or near an end part of the single multi-lumen tube, wherein the semi-permeable dialysis membrane is disposed between the end part of the single multi-lumen tube and the hood.

7. A probe comprising the microfluidic system according to claim 1.

8. The probe according to claim 7, wherein the probe is a multi-lumen probe.

9. The probe according to claim 7, wherein the probe is a dialysis probe.

10. A method of attaching a membrane to a tube, the method comprising the steps of:

providing a single multi-lumen tube defining two or more lumens substantially parallelly arranged side-by-side, the single multi-lumen tube having an end part;

removing an outer portion of the single multi-lumen tube to define a reduced portion in the single multi-lumen tube;

positioning a semi-permeable membrane at said end part of said single multi-lumen tube and over the reduced portion of the single multi-lumen tube, thereby forming a cavity between the reduced portion of the single multi-lumen tube and the semi-permeable membrane;

positioning a fitting member around the semi-permeable membrane and the end part of the single multi-lumen tube, said fitting member being made from a shrinkable material; and

shrinking said fitting member, thereby providing a tight fit between the end part of the single multi-lumen tube, the semi-permeable membrane and the fitting member.

11. The method according to claim 10, wherein the step of shrinking the fitting member comprises heating at least the fitting member to a predefined temperature.

12. The method according to claim 11, wherein the step of shrinking the fitting member comprises heating at least the fitting member to a temperature with the interval 80°

C. to 300°

C.

13. The method according to claim 10, wherein the step of providing a single multi-lumen tube comprises providing a capillary tube.

14. A micro fluidic system prepared by a process comprising the steps of:

providing two or more tubes substantially parallelly arranged side-by-side;

simultaneously heating and stretching in an axial direction the two or more tubes to produce a single multi-lumen tube defining two or more lumens substantially parallelly arranged side-by-side;

removing an outer portion of the single multi-lumen tube that defines at least one of the two or more lumens to produce a reduced portion in the single multi-lumen tube;

positioning a semi-permeable membrane at said end part of said single multi-lumen tube and over the reduced portion of the single multi-lumen tube, thereby forming a cavity between the reduced portion of the single multi-lumen tube and the semi-permeable membrane;

positioning a fitting member around the semi-permeable membrane and the end part of the single multi-lumen tube, said fitting member being made from a shrinkable material; and

shrinking said fitting member, thereby providing a tight fit between the end part of the single multi-lumen tube, the semi-permeable membrane and the fitting member.