FLEXIBLE POLYMER-BASED ENCAPSULATED-FLUID DEVICES

• US 20110303016A1
• Filed: 02/24/2010
• Published: 12/15/2011
• Est. Priority Date: 02/24/2009
• Status: Abandoned Application

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Gutierrez, Christian A., Meng, Ellis
• Application Number:
  US13/202,882
• Publication Number:
  US 20110303016A1
• Time in Patent Office: Days
• US Class Current: 73/719
• CPC Class Codes: G01D 1/00 Measuring arrangements giving results other than momentary value of variable, of general application G01D3/00 takes precedence; in tariff metering apparatus G01D4/00; transducers not specially adapted for a specific variable G01D5/00
• CPC Class Codes: G01D 15/00 Component parts of recorders for measuring arrangements not specially adapted for a specific variable
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
• CPC Class Codes: G01L 9/18 by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electric potential is produced or varied upon the application of stress

Abstract

Embodiments of the present disclosure are directed to MEMS-based medical devices including a flexible housing that forms a chamber for encapsulating a fluid or liquid. The devices also include encapsulated electrodes, portions of which are exposed to the fluid or liquid within the chamber for sensing and/or physical actuation (controlled movement). Such medical devices can function specifically as: contact force sensors; and/or out-of-plane actuators. Device function is enabled by the encapsulation of liquid within the microchamber. Depending on the kind of electrical input applied, the encapsulated electrodes can function as electrochemical sensing elements; and/or electrolytic generation electrodes. Devices according to the present disclosure can have a fluidic coupling to the external environment or can be isolated. Fluidic isolation from the surrounding environment can be accomplished by the inclusion of an annular-plate stiction valve within the device. Related methods of use and fabrication are also described.

Claims

1. An encapsulated-liquid device comprising:

a flexible housing having an interior surface defining a chamber and configured to encapsulate a liquid within the chamber;

first and second fluidic access ports configured to admit liquid into the chamber; and

first and second electrodes, each having a portion exposed to the chamber, wherein the first and second electrodes are configured to sense an impedance of a liquid within the chamber.

2. The device of claim 1 further comprising a stiction valve configured to seal the chamber.

3. The device of claim 2 wherein the housing comprises Parylene.

4. The device of claim 3 wherein the housing comprises Parylene C.

5. The device of claim 2 wherein the first and second fluidic access ports each comprise an internal and external aperture relative to the housing, wherein the internal and external apertures are connected by an access port via.

6. The device of claim 1 wherein the housing is cylindrical and has a diameter from about 25 μ

m to about 1 mm.

7. The device of claim 2 wherein the housing comprises a substrate and wherein the stiction valve comprises a valve plate with a central aperture, wherein the central aperture is configured to admit liquid from the first and second fluidic access ports to the chamber when the valve plate is not in contact with the substrate.

8. An encapsulated-liquid medical device comprising:

a flexible housing having an interior defining a chamber and configured to encapsulate a liquid within the chamber;

first and second fluidic access ports configured to admit liquid into the chamber;

first and second electrodes, each having a portion exposed to the chamber; and

configured to cause electrolysis of a liquid within the chamber; and

at least one electrode disposed on the exterior surface of the housing.

9. The device of claim 8 wherein the wherein at least one electrode comprises a plurality of electrodes.

10. The device of claim 9 wherein the plurality of electrodes is configured as a microelectrode array (MEA).

11. The device of claim 10 wherein the housing comprises Parylene.

12. The device of claim 11 wherein the housing comprises Parylene C.

13. The device of claim 8 further comprising a stiction valve configured to seal the chamber.

14. The device of claim 8 wherein the first and second fluidic access ports each comprise an internal and external aperture relative to the housing, wherein the internal and external apertures are connected by an access port via.

15. The device of claim 8 wherein the housing is cylindrical and has a diameter from about 25 μ

m to about 1 mm.

16. The device of claim 13 wherein the housing comprises a substrate and wherein the stiction valve comprises a valve plate with a central aperture, wherein the central aperture is configured to admit liquid from the first and second fluidic access ports to the chamber when the valve plate is not in contact with the substrate.

17. A method of positioning a surface relative to a device, wherein the medical device includes (i) a flexible housing having a substrate and an interior defining a chamber configured to encapsulate a liquid within the chamber, (ii) first and second electrodes, each having a portion exposed to the chamber, and (iii) and at least one electrode disposed on the exterior surface of the housing, the method comprising:

applying a voltage potential across the first and second electrodes;

causing electrolysis of a liquid within the chamber; and

moving the exterior surface relative to the substrate.

18. The method of claim 17 wherein the at least one electrode disposed on the exterior surface of the housing comprises a microelectrode array (MEA).

19. The method of claim 17 wherein the device further comprises first and second fluidic access ports configured to admit liquid into the chamber.

20. The method of claim 17 wherein the device further comprises a stiction valve.

21. The method of claim 17, wherein the housing of the medical device comprises parylene.

22. The method of claim 17, further comprising encapsulating liquid within the chamber.

23. A method of sensing force applied to a movable surface of a device, wherein the device includes (i) a flexible housing having a substrate, a moveable surface, and an interior defining a chamber configured to encapsulate a liquid within the chamber, and (ii) first and second electrodes, each having a portion exposed to the chamber, the method comprising:

applying a voltage potential across the first and second electrodes;

in response to a force applied to the movable surface, sensing an impedance change of a liquid within the chamber; and

correlating sensed impedance change of the liquid to the force applied to the moveable surface.

24. The method of claim 23 wherein the device further comprises first and second fluidic access ports configured to admit liquid into the chamber.

25. The method of claim 23 wherein the device further comprises a stiction valve.

26. The method of claim 23, wherein the housing of the device comprises parylene.

27. The method of claim 23, further comprising encapsulating liquid within the chamber.