DEVICES AND METHODS FOR SIMULATING A FUNCTION OF A LIVER TISSUE

1 - 12 . (canceled)

13 . A microfluidic device comprising a membrane, said membrane comprising a top surface and a bottom surface, said top surface comprising hepatocytes and said bottom surface comprising endothelial cells and a gel, wherein said gel is between the hepatocytes and said top surface of said membrane, between the endothelial cells and the bottom surface of said membrane, or both.

14 . The microfluidic device of claim 13 , wherein said hepatocytes are primary hepatocytes.

15 . The microfluidic device of claim 13 , further comprising additional cell types over, under or within said gel, said additional cell types selected from the group consisting of Stellate cells and Kupffer cells.

16 - 17 . (canceled)

18 . A method of culturing cells, comprising: a) providing a microfluidic device comprising a membrane, said membrane comprising a top surface and a bottom surface; b) seeding viable dog hepatocytes on said top surface and viable dog endothelial cells on said bottom surface; and c) culturing said seeded cells under flow conditions such that said cells remain viable for at least 28 days.

19 . The method of claim 18 , wherein said dog hepatocytes are primary dog hepatocytes.

20 - 34 . (canceled)

35 . A method of culturing cells, comprising

a) providing

i) a microfluidic device comprising a top chamber, a bottom chamber, and a membrane, said membrane comprising a top surface and a bottom surface,

ii) hepatocytes and endothelial cells and

iii) material capable of forming a gel;

b) introducing said material into said microfluidic device such that a gel forms in said top chamber, in said bottom chamber, or in both chambers; and

c) introducing, in any order,

i) said hepatocytes into said top chamber such that said hepatocytes either affix to said top surface of said membrane or said gel is between said hepatocytes and said top surface of said membrane, and

ii) said endothelial cells such that said endothelial cells either affix to said bottom surface of said membrane or said gel is between said endothelial cells and said bottom surface of said membrane; and

d) culturing said cells under flow conditions with media.

36 . The method of claim 35 , further comprising e) adding additional cell types over, under or within said gel, said additional cell types selected from the group consisting of Kupffer cells and stellate cells.

37 . (canceled)

38 . The method of claim 35 , wherein said microfluidic device further comprises a removable top and said method further comprises, prior to step b), removing said removable top so that said material can be introduced in step b).

39 . The method of claim 35 , wherein said microfluidic device further comprises a removable top and said method further comprises, prior to step c), removing said removable top so that said hepatocytes can be introduced in step c).

40 . The method of claim 35 , wherein said hepatocytes are selected from the group consisting of viable rat hepatocytes, viable dog hepatocytes and viable human hepatocytes.

41 - 46 . (canceled)

47 . A method of culturing cells, comprising

a) providing

i) a microfluidic device comprising a top chamber, a bottom chamber, one or more gels, and a membrane, said membrane comprising a top surface and a bottom surface,

ii) hepatocytes and endothelial cells;

b) introducing, in any order,

i) said hepatocytes into said top chamber such that said hepatocytes either affix to said top surface of said membrane or said gel is between said hepatocytes and said top surface of said membrane, and

ii) said endothelial cells such that said endothelial cells either affix to said bottom surface of said membrane or said gel is between said endothelial cells and said bottom surface of said membrane; and

c) culturing said cells under flow conditions with media.

48 . The method of claim 47 , further comprising d) adding additional cell types over, under or within said gel, said additional cell types selected from the group consisting of Kupffer cells and stellate cells.

49 - 69 . (canceled)

70 . A method for culturing cells, comprising:

a) providing a fluidic device comprising a first structure defining a top chamber, a second structure defining a bottom chamber, and a membrane located at an interface region between the top chamber and the bottom chamber, the membrane including a top side facing toward the top chamber and a bottom side facing toward the bottom chamber;

b) seeding hepatocytes in said top chamber and endothelial cells in said bottom chamber;

c) perfusing at least one of the top chamber and bottom chamber with at least one fluid;

d) disposing a test compound into said fluid, or introducing a second fluid comprising said test compound, such that hepatocytes, endothelial cells or both come in contact with said test compound; and

e) stopping said perfusing in said top chamber, said bottom chamber, or both, so as to increase the residence time of said test compound within said fluidic device.

71 . The method of claim 70 , further comprising f) assessing the clearance of said test compound.

72 . The method of claim 71 , wherein said assessing the clearance comprises measuring the disappearance of said test compound.

73 - 76 . (canceled)

77 . A method for culturing cells, comprising:

a) providing a fluidic device comprising a first structure defining a top chamber, a second structure defining a bottom chamber, and a membrane located at an interface region between the top chamber and the bottom chamber, the membrane including a top side facing toward the top chamber and a bottom side facing toward the bottom chamber;

b) seeding hepatocytes in said top chamber and endothelial cells in said bottom chamber;

c) perfusing at least one of the top chamber or bottom chamber with at least one fluid;

d) disposing a test compound into said fluid such that hepatocytes, endothelial cells or both come in contact with said test compound; and

e) recirculating said fluid so as to increase the interaction time of said test compound with said cells.

78 . The method of claim 77 , further comprising f) assessing the clearance of said test compound.

79 - 84 . (canceled)