Conformal coated microchip reservoir devices

• US 20020187260A1
• Filed: 05/30/2002
• Published: 12/12/2002
• Est. Priority Date: 05/30/2001
• Status: Active Grant

• Current Assignee: MicroCHIPS Inc.
• Original Assignee: MicroCHIPS Inc.
• Inventors: Sheppard, Norman F. Jr., Feakes, Christina M.
• Granted Patent: US 6,973,718 B2
• Time in Patent Office: Days
• US Class Current: 427/248.1
• CPC Class Codes: A61K 9/0009 involving or responsive to electricity, magnetism or acoustic waves; Galenical aspects of sonophoresis, iontophoresis, electroporation or electroosmosis microelectromechanical systems A61K9/0097
• 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: Y10T 29/49146 with encapsulating, e.g., potting, etc.
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

Microchip devices are provided with an inert and biocompatible conformal coating to mitigate adverse responses following device implantation in a patient, to contain and seal a drug or other material within the device, and/or to insulate the electrical connections to the device. The device can include: (1) a substrate having a plurality of reservoirs; (2) reservoir contents, such as a drug or biosensor, in the reservoirs; (3) reservoir caps covering the reservoirs to isolate the contents from environmental components outside the reservoirs; and (4) a conformal coating over the outer surface of at least a portion of the substrate other than the reservoir caps. The reservoir caps can be selectively disintegrated or permeabilized to expose the reservoir contents to environmental components. The conformal coating preferably comprises a vapor depositable polymeric material, such as parylene. Processes for controlling coating of the devices while facilitating reservoir cap exposure are provided.

Claims

1. A microchip device for the controlled release or exposure of molecules or secondary devices comprising:

a substrate having a plurality of reservoirs;

reservoir contents comprising molecules, a secondary device, or both, located in the reservoirs;

reservoir caps covering the reservoirs contents to isolate said contents from one or more environmental components outside the reservoirs, wherein the reservoir caps can be selectively disintegrated or permeabilized to expose the reservoir contents within selected reservoirs to said one or more environmental components; and

a conformal coating over the outer surface of at least a portion of the substrate other than the reservoir caps.

2. The microchip device of claim 1, wherein the conformal coating comprises a vapor depositable polymeric material.

3. The microchip device of claim 1, wherein the conformal coating comprises a poly(para-xylylene).

4. The microchip device of claim 3, wherein the conformal coating comprises Parylene C, Parylene N, Parylene D, or a combination thereof.

5. The microchip device of claim 1, wherein the conformal coating is selected from the group consisting of acrylics, polyurethanes, silicones, and combinations thereof.

6. The microchip device of claim 1, wherein the conformal coating has a thickness between 0.1 and 50 microns.

7. The microchip device of claim 6, wherein the conformal coating has a thickness of about 10 microns.

8. The microchip device of claim 1, wherein the reservoir contents comprise a drug.

9. The microchip device of claim 8, wherein the drug is selected from the group consisting of analgesics, steroids, cytokines, psychotropic agents, chemotherapeutic agents, hormones, anesthetics, vaccines, metabolites, sugars, immunomodulators, antioxidants, ion channel regulators, and antibiotics.

10. The microchip device of claim 1, wherein the reservoir contents comprises molecules selected from the group consisting of proteins, nucleic acids, polysaccharides, and cells.

11. The microchip device of claim 1, wherein the reservoir contents comprises a secondary device.

12. The microchip device of claim 11, wherein the secondary device comprises a sensor or sensor component.

13. The microchip device of claim 1, further comprising a means for disintegrating or permeabilizing the barrier layer.

14. The microchip device of claim 13, further comprising control circuitry to control said means for disintegrating or permeabilizing.

15. The microchip device of claim 14, wherein the control circuitry comprises electrical connections insulated by the conformal coating.

16. The microchip device of claim 14, further comprising a power source.

17. The microchip device of claim 1, wherein reservoir cap comprises a metal membrane.

18. The microchip device of claim 1, wherein the conformal coating covers all exterior surfaces of the device other than the reservoir caps.

19. The microchip device of claim 1, wherein the conformal coating is a laminate structure comprising two layers of parylene and a layer of a metal positioned therebetween.

20. The microchip device of claim 1, wherein the substrate has a front side and a back side, the back side comprising a plurality of reservoir openings distal the reservoir caps on the front side, and the openings are sealed, at least in part, with a barrier layer comprising a conformal coating material.

21. The microchip device of claim 20, wherein the openings are further sealed with a mechanical or chemical sealing system secured over the barrier layer.

22. The microchip device of claim 20, wherein the barrier layer is a laminate structure comprising two layers of a poly(para-xylylene) and a layer of a metal positioned therebetween.

24. The method of claim 23, wherein the conformal coating barrier layer comprises parylene.

25. The method of claim 23, wherein the conformal coating barrier layer is applied by vapor deposition.

26. The method of claim 23, further comprising securing a mechanical or chemical sealing system over the conformal coating barrier layer.

28. The method of claim 27, wherein the conformal coating material comprises parylene.

29. The method of claim 27, wherein the reservoir caps are masked with a masking material before the vapor depositing step.

30. The method of claim 27, wherein any coating material deposited onto the surface of the reservoir caps is subsequently removed.

31. The method of claim 30, wherein the removal is by chemical or plasma etching or by laser.

32. The microchip device of claim 13, wherein the means comprises the application of an effective amount of thermal energy.

33. The microchip device of claim 13, wherein the means comprises an electrochemical reaction.

34. The method of claim 23, wherein the conformal coating barrier layer is a laminate structure comprising two layers of a conformal coating material and a layer of a metal positioned therebetween.

23. A method for sealing reservoirs containing molecules or devices in a microchip device, the method comprising:

providing a substrate having a plurality of reservoirs, a front side, and a back side, the back side comprising a plurality of reservoir openings distal reservoir caps on the front side and in need of sealing;

loading reservoir contents comprising molecules, a secondary device, or both, into the reservoirs; and

applying a conformal coating barrier layer onto the reservoir contents over at least the reservoir openings to seal the reservoir openings.

27. A method of applying a conformal coating to a microchip device comprising:

vapor depositing a conformal coating material onto a microchip device which comprises a substrate having a front side, a back side, and at least two reservoirs containing molecules or devices for selective release or exposure, and reservoir caps positioned on the front side of the substrate on each reservoir over the molecules or devices, wherein release or exposure of the molecules or devices from the reservoir is controlled by diffusion through or disintegration of the reservoir cap; and

providing that the conformal coating does not coat or is removed from the reservoir caps.