Microwell arrays with nanoholes

• US 7,501,279 B2
• Filed: 04/05/2004
• Issued: 03/10/2009
• Est. Priority Date: 04/03/2003
• Status: Expired due to Fees

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Kosar, Turgut Fettah, Folch, Albert
• Primary Examiner(s): Griffin; Walter D
• Assistant Examiner(s): EDWARDS, LYDIA E
• Application Number:
  US10/818,743
• Publication Number:
  US 20060240543A1
• Time in Patent Office: 1,800 Days
• Field of Search: 435/297.5
• US Class Current: 435/297.5
• CPC Class Codes: B01L 2200/0668 Trapping microscopic beads
• CPC Class Codes: B01L 2300/0819 Microarrays; Biochips
• CPC Class Codes: B01L 2400/0409 centrifugal forces
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/043 magnetic forces
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 3/50255 Multi-well filtration
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: C12M 23/16 Microfluidic devices; Capillary tubes integrated microfluidic structures B01L3/5027; microreactors B01J19/0093
• CPC Class Codes: C12M 25/04 in combination with well or multiwell plates, i.e. culture inserts
• CPC Class Codes: G01N 33/48728 Investigating individual cells, e.g. by patch clamp, voltage clamp investigating individual particles in general G01N15/10

Abstract

A device for conducting parallel analysis or manipulation of multiple cells or biomolecules is disclosed. In one embodiment, the device comprises a silicon chip with a microwell, and at least one membrane suspended at the bottom opening of the microwell. The suspended portion of the membrane defines a nanohole that provides access to the material on the other side of the membrane.

Claims

1. A device comprising:

a substrate comprising a plurality of microwells, wherein at least one microwell is adapted to receive fluid, and wherein the microwell comprises a bottom opening;

a membrane disposed on at least one surface of the substrate and suspended below the microwell bottom opening and wherein the suspended portion defines a nanohole; and

a channel layer comprising a plurality of microchannels, wherein the channel layer is positioned such that the membrane is disposed between the substrate and the channel layer and such that a single microchannel is in fluid communication with the microwell via the nanohole,

wherein the microwell and the single microchannel are fluidically isolated from a remainder of the plurality of microwells.

2. The device as claimed in claim 1, wherein the nanohole is sized to permit cells or biomolecules smaller than a designated size through the membrane while retaining larger cells or biomolecules behind the membrane.

3. The device as claimed in claim 1, wherein the nanohole has a diameter ranging in size from about 1 nanometer to about 50 microns.

4. The device as claimed in claim 1, wherein the membrane comprises silicon nitride.

5. The device as claimed in claim 1, wherein the membrane comprises silicon dioxide.

6. The device as claimed in claim 1, wherein the channel layer comprises a polymer.

7. The device as claimed in claim 1, wherein the channel layer comprises poly(dimethylsiloxane).

8. The device as claimed in claim 1, wherein the nanohole is sized to permit a single strand of DNA or protein to pass through the nanohole.

9. The device as claimed in claim 1, wherein the nanohole measures between about 1 to about 3 nanometers in diameter.

10. A method for providing access to a cell or biomolecule comprising:

obtaining a device for containing a cell or biomolecule, wherein the device comprises a plurality of microwells that each comprise a bottom opening, and a membrane positioned below the bottom openings of the plurality of microwells with a separate portion suspended across each bottom opening, wherein each of said suspended portions of the membrane defines a nanohole positioned below the bottom opening of one of the microwells, and wherein each of the plurality of microwells is fluidically isolated from the rest of the plurality of microwells and each of said suspended portions of the membrane is fluidically isolated from the rest of the suspended portions of the membrane; and

positioning the cell or biomolecule on one side of one of the suspended portions of the membrane, such that the cell or biomolecule can be accessed via the nanohole that is defined by said one of the suspended portions of the membrane.

11. The method of claim 10, wherein the device further comprises a microchannel layer, wherein the microchannel layer defines at least one microchannel with an opening under the nanohole.

12. The method of claim 11, wherein the microchannel provides access to the cell or biomolecule.

13. The method of claim 10, further comprising applying suction to the side of the suspended portion of the membrane opposite the cell or biomolecule to position the cell or biomolecule at the nanohole.

14. The method of claim 10, wherein the device is adapted to enable the cell or biomolecule to be automatically guided to the nanohole when suction is applied to the other side of the nanohole to position cell or biomolecule.

15. The method of claim 10, wherein the positioning step is achieved via the microwell.

16. The method of claim 11, wherein the positioning step is achieved via the microchannel.

17. A device comprising:

a substrate defining multiple microwells that are fluidically isolated from each other, wherein each of the microwells defines a bottom opening;

a membrane layer positioned on at least one surface of the substrate and below the bottom opening of at least one of the microwells and defining at least one nanohole, wherein a nanohole is positioned below the bottom opening of a single microwell; and

a polymeric insulator positioned below the membrane layer, wherein the polymeric insulator defines a microchannel positioned below the nanohole in the membrane layer, wherein the membrane layer is at least partially suspended above the microchannel defined by the polymeric insulator,

wherein the membrane layer, the microchannel and the bottom opening of the single microwell are configured such that a fluid contained in the microchannel contacts the membrane layer only at a portion of the membrane which is below the bottom opening of the single microwell.

18. The device as claimed in claim 17, wherein the configuration of the membrane layer, the microchannel and the bottom opening of the single microwell prevents fluid contained in the microchannel from contacting a portion of the membrane layer which is below the substrate.

19. The device as claimed in claim 17, wherein the microchannel has a portion with an area below the bottom opening of the single microwell, which is smaller than the area defined by the perimeter of the bottom opening of the single microwell.

20. A method of manufacturing a device for providing access to cells or biomolecules comprising:

obtaining a substrate with a top side and a bottom side;

forming a membrane layer on the substrate;

forming a plurality of windows in the membrane layer on the top side of the substrate and etching a plurality of microwells in the substrate at the window, wherein the microwells are fluidically isolated from each other;

forming nanoholes in the membrane layer, wherein the nanoholes are positioned on the bottom side of the substrate such that a separate nanohole is positioned under each of the microwells; and

providing channel multiple channels in a channel layer attached to the bottom side of the substrate, wherein each channel is enclosed within the channel layer except for at an opening positioned under the a single nanohole.

21. A method of manufacturing a device for providing access to cells or biomolecules comprising:

obtaining a silicon substrate with a top side and a bottom side;

forming a silicon nitride layer on the substrate;

depositing a metal layer above the silicon nitride layer and creating photoresist islands using a photoresist polymer;

etching a plurality of nanoholes in the silicon nitride layer by reactive ion etching, using a film containing a nanohole as an etch mask;

lithographically etching a plurality of microwell windows in the silicon nitride layer, wherein the microwell windows are positioned opposite the plurality of nanoholes, using the photoresist islands as a guide;

anisotropically etching a microwell at each microwell window such that each microwell is fluidically isolated from the rest of the microwells;

obtaining a channel layer comprising a plurality of channels, with each channel being enclosed within the channel layer except at a single channel opening; and

sealing the channel layer to the silicon nitride such that each channel opening is positioned beneath a separate nanohole.