Substrate-mediated crosstalk between elastic pillars

Cellular traction forces are routinely measured on arrays of flexible microscopic pillars whose deflections are regarded as independent. Here it is shown that vertical deformations of the underlying elastic substrate constitute a coupling between individual pillars. The crosstalk is dominated by a force dipole term that diminishes with the third power of the pillar-to-pillar distance and shows a characteristic angular dependence. The analytical results were verified by finite element simulations and are valid for pillar arrays of any dimensions. For commonly used pillar arrays, the crosstalk between pillars can be neglected. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3463040]