Patterning mammalian cells using elastomeric membranes

We describe the patterning of proteins and cells onto the surfaces of bacte riological Petri dishes, glass, and poly(dimethylsiloxane) (PDMS) with the use of elastomeric lift-off membranes-free-standing polymer films that have circular or square holes with diameters, sides, and height greater than or equal to 50 mu m. Cells are patterned within the physical constraints prov ided by the holes of the membranes; these constraints can be released to al low the cells to spread onto the rest of the surface or to remain in the pa ttern by controlling the properties of the surfaces. Careful control of the properties of the surfaces of the substrates are required to cause the cel ls to adhere to the substrate and not to the membrane, and to avoid damage to the cells on removing the membrane. This strategy of membrane-based patt erning-given the acronym MEMPAT for brevity-offers a more convenient way fo r patterning cells on surfaces and for studying cell spreading than existin g methods.