Microfluid system and method for production thereof

• US 20070197937A1
• Filed: 02/19/2007
• Published: 08/23/2007
• Est. Priority Date: 08/20/2004
• Status: Abandoned Application

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Inventors: Calasso, Irio, Griss, Patrick, Sarofim, Emad
• Application Number:
  US11/676,398
• Publication Number:
  US 20070197937A1
• Time in Patent Office: Days
• US Class Current: 600/583
• CPC Class Codes: A61B 2562/0295 Strip shaped analyte sensors for apparatus classified in A61B5/145 or A61B5/157 disposable multilayered or laminated electrodes G01N27/307; details of handling chemical test elements G01N33/4875
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150282 for piercing elements, e.g. blade, lancet, canula, needle
• CPC Class Codes: A61B 5/150358 Strips for collecting blood, e.g. absorbent optical reagent test strips G01N21/8483; chemical reagent test strips G01N33/4875, G01N33/52
• CPC Class Codes: A61B 5/15045 comprising means for capillary action
• CPC Class Codes: A61B 5/15105 Purely manual piercing, i.e. the user pierces the skin without the assistance of any driving means or driving devices
• CPC Class Codes: A61B 5/15142 Devices intended for single use, i.e. disposable
• CPC Class Codes: B01L 2200/12 Specific details about manufacturing devices
• CPC Class Codes: B01L 2300/0825 Test strips
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 3/502707 characterised by the manufacture of the container or its components by shaping or joining plastic parts B29C59/00, B29C65/00; by laminating B32B37/00; manufacture of microstructural devices in general B81C
• CPC Class Codes: B01L 3/502746 characterised by the means for controlling flow resistance, e.g. flow controllers, baffles B01L3/502738 takes precedence

Abstract

The invention generally concerns a microfluidic system having a support body provided with a lancing member and a semi-open microchannel, for the capillary transport of a sample fluid from a receiving site to a target site. In order to obtain a higher aspect ratio the support body is coated with a build-up layer which laterally defines the microchannel in the upper region.

Claims

1. A microfluidic system for collecting body fluids, the system Comprising:

a support body comprising a lancing member;

a semi-open microchannel, located on the support body such that the microchannel assists in the capillary transport of a fluid from a receiving site to a target site; and

a build-up layer coated on the support body for the fluid transport which laterally defines the microchannel in the upper region.

2. The system according to claim 1, wherein the microchannel has a lower cross-sectional region that is etched into the support body and an overlying upper cross-sectional region formed in the build-up layer.

3. The system according to claim 1, wherein the build-up layer laterally delimits the microchannel over its entire depth.

4. The system according to claim 1, wherein the build-up layer consists of a thick film photoresist.

5. The system according to claim 1, wherein the build-up layer is photostructured in order to form or increase the height of the microchannel.

6. The system according to claim 1, wherein the build-up layer has a layer thickness of more than 50 μ

m.

7. The system according to claim 6, wherein the thickness of the build-up layer is 200 to 500 μ

m.

8. The system according to claim 1, wherein the microchannel has several partial cross-sections etched down into the support body by successive etching steps starting from one surface of the support body.

9. The system according to claim 8, wherein the partial cross-sections are formed by photochemical mask etching.

10. The system according to claim 1, wherein a aspect ratio depth to width of the microchannel is larger than 0.5.

11. The system according to claim 1, wherein the microchannel has an inner width in the range of 50 to 500 μ

m.

12. The system according to claim 1, wherein the microchannel has an undercut in the region of its longitudinal edges formed by underetching.

13. The system according to claim 1, wherein the support body consists of an isotropically etchable material.

14. The system according to claim 1, wherein the support body has a flat shaped part consisting of metal.

15. The system according to claim 14, wherein the support body formed from a flat material has a thickness of 100 to 450 μ

m.

16. The system according to claim 1, wherein the build-up layer has an additional substance or composition which increases the hydrophilicity.

17. The system according to claim 1, wherein the wettability of a wall of the microchannel is increased by a chemical surface treatment.

18. The system according to claim 1, wherein the lancing member is formed by etching or punching and is positioned outside the microchannel.

19. A method of manufacturing a microfluidic system to collect a body fluid, the method comprising:

providing a support body having a lancing member; and

applying a photoresist layer to the support body to form a semi-open microchannel that transports body fluid from a receiving site to a target site.

20. The method according to claim 19, wherein the photoresist is sprayed or knife coated onto the support body as a thick film or is applied by dip coating.

21. The method according to claim 19, wherein the process of forming the microchannel comprises the steps of:

photochemically etching a first photoresist layer;

removing the first photoresist layer;

applying a second photoresist layer and its photostructured in order to increase the height of the microchannel.