Fig. 2: Dynamic imaging and activity maps.
a Electron micrograph of fixed myeloid cells (iStock.com/Dlumen) versus ROCS image of living myeloid cells recorded at 100 Hz. The kymograph shows cell structures moving at 100 Hz. i J774 macrophages imaged with ROCS at 100 Hz (and down-sampled to 10 Hz). The ROI reveals a fast vesicle at 100 Hz, which is invisible at 10 Hz due to motion blur. Intensity kymographs from line scans inside the cell body reveal much higher dynamics at 100 Hz. Right: Snapshot of intensity difference between images at 10 Hz and 100 Hz with line scans in corresponding colors. c Oscillating optical tweezers (100 mW at 1064 nm) induce activity in the cell cortex of J774 macrophages. Non-TIR darkfield ROCS-image sequence In(x,y) recorded at NA = 0.8 hardly reveal any cellular responses left to the red arrow. Activity maps σ(x, y, Δω) reveal cortex activity at 3 different timescales (Δω−1 = 0.1–1 s, 0.03–0.1 s, 10–30 ms) within ROI (white box). Slow motions correspond to small σ (black) and fast motions to a large σ (yellow). Switching the optical tweezers off stops cortex activity immediately. Source data are provided as a Source Data file.
