A large-scale balloon model of confluent cells validates stress inference from geometry.

The mechanical environment surrounding cells influences their behavior. Multiple methods have been developed to measure local mechanics with mechanical perturbation, which is invasive. For sheets of confluent cells, the geometry of the boundaries of the cells can be used to estimate the local membrane tension and internal cell pressure through stress inference (SI), which is image-based and therefore non-invasive. SI is sensitive to noise and has not been validated in a physical system using a direct pressure measurement. We developed a large-scale model of confluent cells using densely-packed balloons with interior pressure sensors to allow for simultaneous measurement of pressure and geometry. We also developed a new SI method which resulted in a correlation coefficient >0.8 with the balloon model, less noise sensitivity in computational models, and measured pressure change in red onion epithelial cells. These results demonstrate the validity and utility of SI in multiscale physical and computational applications.