Super-Resolution Axial Imaging for Quantifying Piconewton Traction Forces in Live-cells

Cell mechanics play a pivotal role in regulating numerous biological processes. While super-resolution microscopy enables the imaging of cellular forces in the lateral dimension with sub-10-nanometer resolution, achieving comparable resolution along the axial dimension remains a significant challenge. In this study, we combine metal-induced energy transfer (MIET) imaging with novel DNA-hairpin-based molecular tension probes (MIET-MTP) to map integrin-mediated mechanical forces with nanometer precision in the axial direction. MIET-MTP allows for the simultaneous observation of both the plasma membrane and forceexerting molecules in the axial dimension. Using this approach, we mapped axial integrin tension in focal adhesions and podosomes, alongside their corresponding plasma membrane height profiles, offering detailed insights into the structures involved in force transmission.