Patent ID: 7749728

Claim:
A method of measuring the penetration of a test substance within a multi-layered cell culture comprising: (a) providing a multi-layered cell culture disposed on a permeable support membrane, the cell culture having a first side and a second side; (b) maintaining said first side and said second side of said cell culture in contact with a liquid growth medium in a reservoir, wherein cells in said cell culture proximate said first side and said second side are proliferating at similar rates; (c) sealing off said second side of said cell culture such that said second side is not in contact with said liquid growth medium for a discrete period of time, wherein said discrete period is selected such that said cells proximate said first side and said second side continue proliferating at similar rates; (d) exposing said test substance to said first side of said cell culture during said discrete period; and (e) analyzing said cell culture after said discrete period time to determine the degree of penetration of said test substance within said multi-layered cell culture.