Patent ID: 8865464

Claim:
A method, comprising: a) providing a substrate comprising a reservoir formed in the substrate and having upper and lower portions, the upper portion being sized to permit the insertion and removal of a cell mass from the reservoir; and a passage at least partially formed in the substrate and in fluid communication with the reservoir wherein a surface of the passage comprises a deformable membrane comprising a plurality of layers, wherein a first layer comprises a deformable elastomer and a second layer comprises a non-rigid polymer that blocks moisture; b) inserting a cell mass in a reservoir of said substrate under conditions, wherein said lower portion of said reservoir has a width less than 250 micrometers to retain at least a portion of the cell mass within the lower portion of the reservoir, wherein said cell mass is prevented from entering said passage and the cell mass can be directly removed from the lower portion through the upper portion; and c) culturing said cell mass in said reservoir such that said cell mass grows.