TGFB1 and idiopathic pulmonary fibrosis: IPF-fibroblasts exhibited consistently larger mRNA COL1A1 levels when cultured in stiff substrata in the presence of TGF-β1 compared to fibroblasts from control tissue, although to a larger extent in 3D gels (~1.7-fold) (Figure 6A) than 2D PAA gels (~1.2-fold) (Figure 6B).