Life on a bed of needles

Cells pull on their environment during adhesion, contraction, or movement, but mapping those forces is no easy task. Past methods have relied on the wrinkling or deformation of a pliant substrate—akin to the scrunching of a sheet when someone sits down on a bed. Now, John Tan, Christopher Chen, and colleagues (Johns Hopkins University, Baltimore, MD) have put forward an alternative method using arrays of microfabricated, bendy posts.

The wrinkling methods map the location of the forces indirectly and rely on deconvolving one of several possible solutions. But, says Chen, “because the posts move independently, if a post moves you know it's because the cell is pulling on it—there's really no other explanation. For the other methods you need to know where the adhesions are, or make other assumptions.” For example, the new method would spot the...