Develop a non-damaging stamping protocol for soft PDMS to enable open-strip traction force experiments

Develop a reproducible method to place and remove a stamp on soft PDMS substrates (approximately 3 kPa) for open-strip geometries without damaging either the MDCK cell monolayer or the PDMS substrate, thereby enabling unbiased and reproducible traction force microscopy in open strip experiments with a free front.

Background

The study measures traction forces in racetrack geometries using a soft PDMS substrate (Young modulus ~3 kPa), revealing force peaks at confining boundaries consistent with vimentin staining. To compare force transmission between closed racetracks and open strips with a free front, traction force microscopy would need to be performed in open-strip geometries on soft substrates.

However, the authors report that the soft PDMS used is very fragile and sticky, and they have been unable to devise a stamping procedure that allows placement and removal of the stamp without damaging the cell monolayer or the substrate. This methodological obstacle prevents reproducible, unbiased traction force measurements in open-strip setups, leaving the development of a suitable soft-PDMS stamping protocol as an unresolved practical problem.