Quantifying cellular forces and biomechanical properties by correlative micropillar traction force and Brillouin microscopy.

Cells sense and respond to external physical forces and substrate rigidity by regulating their cell shape, internal cytoskeletal tension, and stiffness. Here we show that the combination of micropillar traction force and noncontact Brillouin microscopy provides access to cell-generated forces and intracellular mechanical properties at optical resolution. Actin-rich cytoplasmic domains of 3T3 fibroblasts showed significantly higher Brillouin shifts, indicating a potential increase in stiffness when adhering on fibronectin-coated glass compared to soft PDMS micropillars. Our findings demonstrate the complementarity of micropillar traction force and Brillouin microscopy to better understand the relation between cell force generation and the intracellular mechanical properties.