Micromachined porous membranes with bulk support

• US 5,985,328 A
• Filed: 01/28/1998
• Issued: 11/16/1999
• Est. Priority Date: 03/07/1994
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Ferrari, Mauro, Chu, Wen-Hua
• Primary Examiner(s): Drodge, Joseph W.
• Application Number:
  US09/014,727
• Time in Patent Office: 657 Days
• Field of Search: 210/321, 210/84, 210/490, 210/491, 210/500.22, 210/500.25, 210/500.26, 210/650, 210/651, 424/424, 424/451, 424/489, 604/890.1, 604/891.1, 604/892.1, 216/2, 216/56, 264/4, 428/312.6
• US Class Current: 424/489
• 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: B01D 2325/02 Details relating to pores or porosity of the membranes
• CPC Class Codes: B01D 2325/0283 Pore size
• CPC Class Codes: B01D 2325/04 Characteristic thickness
• CPC Class Codes: B01D 39/1692 Other shaped material, e.g. perforated or porous sheets
• CPC Class Codes: B01D 39/20 of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires porous ceramic material C04B38/00 ; sintering metals C22C1/04; making porous sintered metal bodies B22F3/10, honeycomb filters B01D46/2418, materials used for filtering exhaust gases of an internal combustion engine F01N3/022, ceramic honeycomb structures C04B38/0006
• CPC Class Codes: B01D 67/0058 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B01D 67/0062 by micromachining techniques, e.g. using masking and etching steps, photolithography
• CPC Class Codes: B01D 67/0072 by deposition from the gaseous phase, e.g. sputtering, CVD, PVD
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/12 Composite membranes; Ultra-thin membranes
• CPC Class Codes: B01D 71/02 Inorganic material
• CPC Class Codes: B01D 71/0213 Silicon
• CPC Class Codes: B01J 13/02 Making microcapsules or microballoons for medical preparations A61K9/50
• CPC Class Codes: B81B 2201/10 Microfilters, e.g. for gas or fluids
• CPC Class Codes: B81C 1/00087 Holes
• CPC Class Codes: B81C 2201/014 by depositing an etch stop layer, e.g. silicon nitride, silicon oxide, metal
• CPC Class Codes: B81C 2201/032 LIGA process
• CPC Class Codes: C04B 41/4582 Porous coatings, e.g. coating containing porous fillers
• CPC Class Codes: C23C 16/01 : on temporary substrates, e.g. substrates subsequently removed by etching
• CPC Class Codes: G03F 7/00 : Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor using photoresist structures for special production processes, see the relevant places, e.g. B44C, H01L, e.g. H01L21/00, H05K
• CPC Class Codes: G03F 7/0015 : Production of aperture devices, microporous systems or stamps

Abstract

A microfabricated containment capsule has a bulk substrate delimiting a cavity with a boundary, a first portion of which constitutes an inner wall of a solid portion of the bulk substrate. The bulk substrate also provides at a second portion of the boundary a membrane joined to one side of the bulk substrate, the membrane having at least one porous area with controlled pores.

Claims

1. A microfabricated containment capsule, comprising:

a. at least one bulk substrate, said at least one bulk substrate delimiting a cavity having a boundary, a first portion of said boundary constituting an inner wall of a solid portion of said at least one bulk substrate; and

b. at a second portion of said boundary, a membrane having at least one porous area with controlled pores and a rib member, said membrane joined to one side of said at least one bulk substrate to provide a selective molecular barrier for passing molecules dimensioned at less than about 3,500 angstroms between an interior and an exterior of said cavity.

2. The containment capsule of claim 1 wherein an exposed surface of said capsule comprises a biocompatible material.

3. The containment capsule of claim 1 wherein said at least one porous area comprises a microfabricated thin-film membrane filter.

4. The containment capsule of claim 1 wherein said containment capsule includes multiple parts bonded by a sealant.

5. The containment capsule of claim 4 wherein said sealant is a biocompatible, polymeric material.

6. The containment capsule of claim 1 wherein the size of the pores allows free diffusion of a biologically active molecule produced inside said capsule, but prevents passage of immunological molecules located outside said capsule.

7. The containment capsule of claim 6 wherein the size of the pores is between about 10 angstroms and about 10000 angstroms.

8. The containment capsule of claim 7 wherein the size of the pores is between about 20 angstroms and about 500 angstroms.

9. The containment capsule of claim 6 wherein the interior of said capsule is treated with a first organic layer that donor cells will adhere to, and the exterior of said capsule is treated with a second organic layer that host cells will not adhere to.

10. A method of providing a biologically active molecule in a host organism, comprising:

a. microfabricating a biocompatible containment capsule having a bulk substrate portion, a rib support member and a porous membrane joined to one side of the bulk substrate portion to prevent passage of immunological molecules into said containment capsule while permitting diffusion at a physiologically desirable rate of a biologically active molecule produced by a cell, tissue or pharmaceutical composition inside said containment capsule; and

b. administering to said host organism, said cell, tissue or pharmaceutical composition contained within said containment capsule.

11. The method of claim 10 wherein said organism is an animal.

12. The method of claim 11 wherein said animal is a mammal.

13. The method of claim 12 wherein said mammal is a human.

14. A containment capsule, comprising:

a. at least one bulk substrate, said at least one bulk substrate etched to form a cavity having a boundary, a first portion of said boundary constituting an inner wall of a solid portion of said at least one bulk substrate; and

b. at a second portion of said boundary, a membrane having at least one porous area with controlled pores and a structural support member, said membrane providing a selective molecular barrier for passing molecules dimensioned at less than about 3,500 angstroms between an interior and an exterior of said cavity.

15. A method of providing a biologically active molecule in a host organism, comprising:

a. providing a biocompatible containment capsule having an etched bulk substrate portion and a thin-film membrane portion having a structural support member and joined to one side of the etched bulk substrate portion that permits diffusion of a biologically active molecule dimensioned at less than about 3,500 angstroms produced by a cell, tissue or pharmaceutical composition inside said containment capsule at a physiologically desirable rate, but prevents passage of immunological molecules located outside said containment capsule;

b. filling said containment capsule with a cell, tissue or pharmaceutical composition capable of producing said biologically active molecule; and

c. administering to said host organisms, said cell, tissue or pharmaceutical composition contained withing said capsule.