Fig. 1

Deformation of cartilage micropellets induced by mechanical stimulations with square pressure signals of different amplitudes. A Sinking of micropellets in their cones observed with a 2.65 µm resolution camera. B Average diameter of micropellets studied in each group (n = 11–20 micropellets). C Average sinking of micropellets in their cones at the beginning (Initial) and end (Final) of 30 min of stimulation depending on the pressure amplitude (n = 11–20 micropellets). D Average amplitude of cyclic oscillations of the micropellet top and bottom ends depending on pressure amplitude (n = 11–20 micropellets). E Localization of radial (Er), circumferential (Eθ) and longitudinal (Ez) strains, the von Mises strains (Evm) and the volume change of micropellets during stimulation with the 7 kPa pressure amplitude, from left to right respectively, shown by a finite element model. (F) Distribution in volume of Er, Eθ, Ez and volume change in micropellets depending on pressure amplitudes and estimated by the finite element model. Statistical analysis used Kruskal–Wallis test (*: p < 0.05, **: p < 0.01, ***: p < 0.001) or Wilcoxon matched-pairs signed rank test (###: p < 0.001, ####: p < 0.0001)