showed a more pronounced decrease in F-actin expression relative to the static control than the hLFs grown on top of the softer hydrogels (3% GelMA), which was the expected trend. However, it is worth noting that the response to the substrate stiffness could be different for the 3T3 fibroblasts and the hLFs and the stretching parameters used were not identical, meaning that the stiffness of the hydrogel was not the only experimental variable. Overall, these results show that the 3D printed GelMA-CBP models could mimic the lung dynamic environment and produce relevant biological readouts, but that additional research is needed to pinpoint the differences Quantification of (C) αSMA and (D) F-actin expression from HLFs cultured under static and cyclic stretch conditions. Statistically significant differences are indicated with * for p < 0.05. A twotailed t-test was employed for comparisons between two groups. Data is presented as the mean and standard deviation for n ≥ 3 independently prepared samples.