Porous membrane apparatus, method, and applications

1. A method of producing a three-dimensional porous membrane in a microfluidic chamber, the method comprising the steps of:

applying a photoresist material onto the microfluidic chamber to form a photoresist material layer, wherein the microfluidic chamber comprises a plurality of silicon pillars;

exposing a peripheral portion of the photoresist material layer to radiation, wherein exposing the photoresist material layer to radiation cross-links the exposed peripheral portion to the microfluidic chamber;

masking, using a mask comprising a plurality of pores formed therein, the photoresist material layer;

exposing a top layer of the masked photoresist material layer to radiation to form a porous membrane layer of cross-linked photoresist material;

removing non-exposed photoresist material from under the porous membrane layer;

air-drying the porous membrane layer such that the porous membrane layer adopts, as it dries, a three-dimensional shape corresponding to the plurality of silicon pillars; and

removing, via etching, the plurality of silicon pillars, wherein the air-dried porous membrane layer retains, after etching, the three-dimensional shape corresponding to the plurality of silicon pillars.

2. The method of claim 1 , further comprising the step of:

etching a portion of the microfluidic chamber to create the plurality of silicon pillars.

3. The method of claim 1 , further comprising the steps of:

applying a first polymer material onto the microfluidic chamber to form a first polymer layer.

4. The method of claim 3 , further comprising the step of removing the first polymer material.

5. The method of claim 1 , wherein the photoresist material is SU-8.

6. The method of claim 3 , wherein the steps of applying the first polymer material onto the etched microfluidic chamber and applying the photoresist material comprise spin coating.

7. The method of claim 1 , wherein the step of removing the non-exposed photoresist material from under the porous membrane layer comprises incubating in photoresist material developer.

8. The method of claim 2 , wherein said etching step comprises the steps of:

applying an initial photoresist material onto the microfluidic chamber to form an initial photoresist material layer;

exposing the initial photoresist material layer to radiation in a predetermined pillar array pattern;

etching the microfluidic chamber to create a plurality of silicon pillars corresponding to the predetermined pillar array pattern formed in the exposed initial photoresist material layer; and

removing all of the initial photoresist material.

9. The method of claim 1 , further comprising the steps of:

seeding the porous membrane layer with a plurality of cells; and

incubating the seeded porous membrane layer under conditions suitable to promote growth of said seeded cells.

10. The method of claim 9 , wherein said plurality of cells are Caco-2 cells.

11. A method of producing a porous membrane in a microfluidic chamber, the method comprising the steps of:

applying a photoresist material onto the microfluidic chamber to form a photoresist material layer;

exposing a peripheral portion of the photoresist material layer to radiation, wherein exposing the photoresist material layer to radiation cross-links the exposed peripheral portion to the microfluidic chamber;

masking, using a mask comprising a plurality of pores formed therein, the photoresist material layer;

exposing a top layer of the masked photoresist material layer to radiation to form a porous membrane layer of cross-linked photoresist material;

removing the non-exposed photoresist material from under the porous membrane layer;

drying the porous membrane layer such that the porous membrane layer adopts, as it dries, a three-dimensional shape corresponding to the plurality of silicon pillars; and

removing, via etching, the plurality of silicon pillars, wherein the dried porous membrane layer retains the three-dimensional shape corresponding to the plurality of silicon pillars after etching.

12. The method of claim 11 , wherein the photoresist material is SU-8.

13. The method of claim 11 , wherein the method further comprises, prior to said masking step, the step of:

exposing a central portion of the photoresist material layer to radiation, wherein a plurality of cross-linked support posts are created in said photoresist material layer.

14. The method of claim 11 , further comprising the step of:

seeding the porous membrane layer with a plurality of cells; and

incubating the seeded porous membrane layer under conditions suitable to promote growth of said seeded cells.