MEMS DEVICE AND METHOD FOR DELIVERY OF THERAPEUTIC AGENTS

• US 20080039792A1
• Filed: 03/14/2007
• Published: 02/14/2008
• Est. Priority Date: 03/14/2006
• Status: Active Grant

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Agrawal, Rajat, Meng, Ellis, Tai, Yu-Chong, Kuwahara, Kenrick, Shih, Jason, Humayun, Mark, Rodger, Damien, Lo, Ronalee, Li, Po-Ying, Chen, Po-Jui
• Granted Patent: US 7,887,508 B2
• Time in Patent Office: Days
• US Class Current: 604/114
• CPC Class Codes: A61F 9/0017 implantable in, or in contact with, the eye, e.g. ocular inserts
• CPC Class Codes: A61K 9/0024 Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue compositions for intravenous administration, normal injectable solutions or dispersions for, e.g. subcutaneous administration A61K9/0019; brain implants A61K9/0085; (coated) prostheses, catheters or stents A61L
• CPC Class Codes: A61K 9/0097 Micromachined devices; Microelectromechanical systems [MEMS]; Devices obtained by lithographic treatment of silicon; Devices comprising chips intradermal microneedle arrays A61K9/0021; MEMS in general B81B7/02
• CPC Class Codes: A61M 2005/14204 with gas-producing electrochemical cell
• CPC Class Codes: A61M 2205/0244 Micromachined materials, e.g. made from silicon wafers, microelectromechanical systems [MEMS] or comprising nanotechnology
• CPC Class Codes: A61M 2205/3507 with implanted devices, e.g. external control
• CPC Class Codes: A61M 2207/00 Methods of manufacture, assembly or production
• CPC Class Codes: A61M 2210/0612 Eyes
• CPC Class Codes: A61M 37/00 Other apparatus for introducing media into the body for reproduction or fertilisation A61B17/425; apparatus for iontophoresis or cataphoresis A61N1/30; Percutany, i.e. introducing medicines into the body by diffusion through the skin salt baths A61H33/04
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/14593 the diaphragm being actuated by fluid pressure
• CPC Class Codes: A61M 5/155 pressurised by gas introduced into the reservoir
• CPC Class Codes: A61M 5/16877 Adjusting flow; Devices for setting a flow rate
• CPC Class Codes: A61M 5/16881 Regulating valves on-off valves, e.g. clamps A61M39/28
• CPC Class Codes: B81B 2201/058 Microfluidics not provided for in B81B2201/051 - B81B2201/054
• CPC Class Codes: B81C 1/00119 Arrangement of basic structures like cavities or channels, e.g. suitable for microfluidic systems
• CPC Class Codes: B81C 2201/019 Bonding or gluing multiple substrate layers
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F16K 2099/008 Multi-layer fabrications
• CPC Class Codes: F16K 2099/0088 Implanted devices
• CPC Class Codes: F16K 99/0001 : Microvalves microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006
• CPC Class Codes: F16K 99/0005 : Lift valves
• CPC Class Codes: F16K 99/0034 : Operating means specially adapted for microvalves
• CPC Class Codes: F16K 99/0057 : the fluid being the circulating fluid itself, e.g. check valves
• CPC Class Codes: Y10T 29/49236 : Fluid pump or compressor making

Abstract

An implantable device for delivering a therapeutic agent to a patient is provided. The device includes a reservoir configured to contain a liquid comprising the therapeutic agent. The device further includes a cannula in fluid communication with the reservoir. The cannula has an outlet configured to be in fluid communication with the patient. The device further includes a first electrode and a second electrode, at least one of the first electrode and the second electrode is planar. The device further includes a material in electrical communication with the first and second electrodes. A voltage applied between the first electrode and the second electrode produces gas from the material, the gas forcing the liquid to flow from the reservoir to the outlet.

Claims

1. An implantable device for delivering a therapeutic agent to a patient, the device comprising:

a reservoir configured to contain a liquid comprising the therapeutic agent;

a cannula in fluid communication with the reservoir, the cannula having an outlet configured to be in fluid communication with the patient; and

a valve comprising a movable element movable between a first position and a second position, the movable element comprising an orifice therethrough, wherein the liquid flows through the orifice to the outlet when the movable element is in the first position and wherein the liquid does not flow through the orifice to the outlet when the movable element is in the second position.

2. The device of claim 1, wherein the reservoir comprises a first wall which is generally puncturable by a needle, thereby allowing refilling of the reservoir through the needle.

3. The device of claim 2, wherein the first wall reseals itself upon removal of the needle.

4. The device of claim 2, wherein the reservoir further comprises a second wall which is generally unpuncturable by the needle.

5. The device of claim 1, wherein the cannula comprises an end insertable into the patient and comprising the outlet.

6. The device of claim 5, wherein the end of the cannula is tapered.

7. The device of claim 5, wherein the valve is at the end of the cannula.

8. The device of claim 1, wherein the movable element comprises a flexible portion of a wall of the cannula.

9. The device of claim 8, wherein the valve comprises a valve seat, the portion of the wall is not in contact with the valve seat when the movable element is in the first position, and the portion of the wall is in contact with the valve seat when the movable element is in the second position.

10. The device of claim 1, wherein the valve comprises a valve seat within the cannula, the valve seat comprising a protrusion extending from an inner surface of the cannula towards the movable element.

11. The device of claim 1, wherein the movable element moves from the second position to the first position in response to pressure applied to the movable element by fluid within the cannula.

12. An implantable device for delivering a therapeutic agent to a patient, the device comprising:

a reservoir configured to contain a liquid comprising the therapeutic agent;

a cannula in fluid communication with the reservoir, the cannula having an outlet configured to be in fluid communication with the patient;

a first electrode and a second electrode, at least one of the first electrode and the second electrode is planar; and

a material in electrical communication with the first and second electrodes, wherein a voltage applied between the first electrode and the second electrode produces gas from the material, the gas forcing the liquid to flow from the reservoir to the outlet.

13. The device of claim 12, wherein the first electrode and the second electrode are both planar.

14. The device of claim 13, wherein the first electrode and the second electrode are co-planar with one another.

15. The device of claim 14, wherein the first electrode and the second electrode are interdigitated with one another.

16. The device of claim 12, wherein the first electrode and the second electrode comprise gold, palladium, or platinum.

17. The device of claim 12, wherein the material comprises water and the gas comprises hydrogen gas and oxygen gas.

18. A method of making an implantable device for delivering a therapeutic agent to a patient, the method comprising:

forming a plurality of structural layers; and

bonding the plurality of structural layers together to form a reservoir configured to contain a liquid and a cannula in fluid communication with the reservoir, the cannula having an outlet configured to be in fluid communication with the patient.

19. The method of claim 18, wherein forming the plurality of structural layers comprises forming at least one structural layer using a lithographic process.

20. The method of claim 19, wherein the lithographic process comprises:

providing a substrate;

forming a patterned photoresist layer on the substrate, wherein the photoresist layer covers a first portion of the substrate and does not cover a second portion of the substrate;

etching the second portion of the substrate;

removing the patterned photoresist layer;

forming a mold release layer on the substrate;

forming the structural layer on the mold release layer; and

removing the structural layer from the substrate.

21. The method of claim 20, wherein the mold release layer comprises parylene.

22. The method of claim 20, wherein the structural layer comprises polydimethylsiloxane.

23. The method of claim 18, wherein at least one structural layer comprises a first electrode and a second electrode, and forming the at least one structural layer comprises:

providing a substrate;

forming a dielectric layer over the substrate;

forming the first electrode and the second electrode over the dielectric layer;

remove a portion of the dielectric layer to expose a portion of the substrate;

forming a first sacrificial layer over the exposed portion of the substrate;

forming a first structural layer over the first sacrificial layer, the first structural layer serving as a bottom wall of the cannula;

forming a second sacrificial layer over the first structural layer;

forming a second structural layer over the second sacrificial layer, the second structural layer serving as top and side walls of the cannula;

patterning the first structural layer and the second structural layer;

forming a third structural layer over the dielectric layer, the third structural layer serving as a portion of the reservoir;

removing the first and second sacrificial layers; and

removing a portion of the substrate below the first and second structural layers.

24. The method of claim 23, wherein the first structural layer and the second structural layer comprise parylene.

25. A method of delivering a therapeutic agent to a patient, the method comprising:

providing a device implanted in or on a patient, the device comprising;

a reservoir containing a liquid comprising the therapeutic agent;

a cannula in fluid communication with the reservoir, the cannula having an outlet in fluid communication with the patient; and

a first electrode, a second electrode, and a material in electrical communication with the first and second electrodes;

applying a first voltage between the first electrode and the second electrode to produce gas from the material, the gas forcing the liquid to flow from the reservoir to the outlet; and

applying a second voltage between the first electrode and the second electrode to produce the material from the gas.

26. The method of claim 25, wherein the material comprises water and the gas comprises hydrogen gas and oxygen gas.

27. The method of claim 25, wherein the first voltage and the second voltage are opposite in sign.