Fig. 1

Cell morphology changes of chondrocytes in response to PDMS substrates with different stiffnesses. a Representative SEM images showing the cell morphology changes of chondrocytes seeded onto PDMS substrates with stiff (450 kPa) and soft (46 kPa) stiffnesses. Yellow arrows indicates cellular synapses. b Box and whisker plot showing the changes of cell spreading areas of chondrocytes seeded onto PDMS substrates with stiff (450 kPa) and soft (46 kPa) stiffnesses. Twenty-eight cells per group from eight independent experiments were used to calculate the cell spreading areas. c Box and whisker plot showing the changes of cellular synapses of chondrocytes seeded onto PDMS substrates with stiff (450 kPa) and soft (46 kPa) stiffnesses. Twenty-eight cells per group from eight independent experiments were used to calculate the cellular synapses. d Box and whisker plot showing the changes of cellular synapse lengths of chondrocytes seeded onto PDMS substrates with stiff (450 kPa) and soft (46 kPa) stiffnesses. Two hundred and eighty cellular synapses of twenty-eight cells from the stiff group and one hundred and twenty-five cellular synapses of twenty-eight cells from the stiff group were applied to calculate the cellular synapse lengths. The SEM experiments are based on eight independent experiments (n = 8). The data in (b), (c), & (d) are shown in the box (from 25%, 50% to 75%) and whisker (minimum to maximum values) plots. All significant data presented in (b), (c) & (d) are based on two-tailed Student’s t-tests.