Aggregation-Based Fluorescent Probe for Visualizing Cell Membrane Tension Dynamics

The cell membrane undergoes dynamic tension changes that regulate cell migration, division, and disease progression, yet quantifying these changes remains challenging due to spatiotemporal heterogeneity. Existing approaches, including Förster resonance energy transfer (FRET)-based tension sensors, optical tweezers, and fluorescence lifetime imaging, often require genetic manipulation or specialized instrumentation, limiting accessibility. Importantly, membrane tension is tightly coupled to lipid packing of a single-phase membrane, where higher tension or compression directly induces a looser or denser lipid organization, respectively. Leveraging this principle, we developed TensiLux (derived from ‘tension’ and the Latin ‘lux’ for light), an aggregate-monomer fluorescent probe forming red-emissive aggregates in densely packed domains and green-emissive monomers in loosely packed regions. TensiLux enables ratiometric visualization of lipid organization and relative membrane tension changes in model membranes and living cells under varying mechanical conditions, including 2D-confined mesenchymal-to-amoeboid transition. This provides a simple, genetically independent and broadly accessible tool for investigating membrane mechanobiology.