Human monocyte mechanics is affected by strain rate and CCL2 treatment
(A) Schematic representation of OT, in which a monocyte is sandwiched between two optically trapped beads.
(B) Morphological changes of a monocyte after treatment with 200 ng/mL of CCL2 for 15 min prior to bead attachment.
(C) Typical trace of recorded force versus time at RT, PT, and upon stimulation by CCL2.
(D) Dynamic stiffness of monocytes at RT, PT, and after treatment with CCL2 fitted by a power law model. CCL2-treated cells could not be fitted by the power-law function, and only data points are shown.
(E) Power exponent of stress-relaxation analysis as a function of strain rate at RT and PT showed a significant difference (p < 0.0001).
(F) In case of CCL2-treated cells, power exponent revealed strain-rate dependent changes; 0.20 ± 0.04 for velocities from 1 to 5 μm/s and 0.36 ± 0.03 for velocities from 7 to 20 μm/s (p value = 0.002). Data are represented as mean ± SEM.