Molecular to cellular mechanics probed by high-speed force spectroscopy
The mechanical properties of individual proteins, filaments, and supramolecular assemblies provide structural stability and mechanical flexibility to the living cell. Thus, molecular understanding of the mechanics from the single molecule to the whole cell is relevant to understand biological function. High-speed atomic force microscopy (HS-AFM) is a unique technology allowing subsecond, nanometric imaging (1). We have recently adapted HS-AFM to perform high-speed force spectroscopy (HS-FS) to probe protein unfolding at the speed of molecular dynamics simulations (2). This combination provides a unique method to acquire atomistic understanding of biomolecular processes based on experimental results. We have now gone a step further in the adaptation of HS-AFM to probe the mechanics of cells at high frequencies, up to 100 kHz. We report the viscoelastic response of different cell types and upon cytoskeletal drug treatments. At previously inaccessible short timescales, cells exhibit rich viscoelastic responses that depend on the state of the cytoskeleton and the cell type. Microrheology over a wide dynamic range up to the frequency of action of the molecular components provides a mechanistic understanding of cell mechanics.
- T. Ando et al., A high-speed atomic force microscope for studying biological macromolecules. Proceedings of the National Academy of Sciences 98, 12468 (October 23, 2001, 2001).
- F. Rico, L. Gonzalez, I. Casuso, M. Puig-Vidal, S. Scheuring, High-Speed Force Spectroscopy Unfolds Titin at the Velocity of Molecular Dynamics Simulations. Science 342, 741 (November 8, 2013, 2013).