Atomic Force Microscopy of Ocy454 Cells

Ocy454 cells were plated onto 22 mm × 22 mm glass coverslips and allowed to grow for 16 to 24 hours at 37°C and 5% CO₂ with α-MEM. Thereafter, cells were washed with phosphate-buffered saline (PBS) before being incubated with pharmacological agents as indicated for 2 hours at 37°C and 5% CO₂ in α-MEM. After each treatment, cells were transferred to 60-mm culture dishes with prewarmed Hepes-based medium containing identical concentrations of the previously mentioned agents. Cells were probed with an MFP-1D atomic force microscope (Asylum Research) (64 (link), 65 (link)) using MLCT cantilevers (Bruker) with a nominal spring constant of k = 0.01 N/m. The pull distance used was 2 μm with a tip velocity of 4 μm/s to generate ~1 to 2 nN of force onto the cell corresponding to ~1-μm indentation, ensuring that the cytoskeleton was effectively being probed. The elastic moduli (stiffness) of the cells were calculated using the Sneddon-Hertz model, which has been described (66 (link)).