▎ 摘　　要

NOVELTY - Performing lithographic masking involves providing a group of cells on a substrate; coating a layer of gelatin on a portion of the cells; creating a mask layer on a portion of the layer of gelatin on a portion of the cells; and creating an area of masked cells and an area of unmasked cells. USE - Method for performing lithographic masking for spatially localized biochemical stimulus delivery. ADVANTAGE - The method solves long-standing problems by introducing tunably permeable membranes as cellular masks, avoiding the need for complicated microfluidic device fabrication to achieve spatially heterogeneous cell cultures. The method also overcomes the challenge of developing complicated single-purpose microfluidic devices to investigate cell-cell behavior, while maintaining the ability to study populations of cells interacting with one another. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing product of the process of lithographic masking for spatially localized biochemical stimulus delivery, which involves: (1) creating a first population of cells on a substrate; (2) coating a layer of gelatin on a portion of the first population of cells on the substrate; (3) creating a mask layer on a portion of the layer of gelatin on the first population of cells; (4) creating an area of masked cells and an area of unmasked cells; (5) removing or trypsinizing cells from the unmasked area; seeding with a second population of cells; (6) creating a second population of cells; (7) removing the mask layer; (8) creating a spatially patterned co-culture; and (9) allowing cells from the first population of cells and cells from the second population of cells to interact freely.