Sun et al. (2020) utilized 3D printing and electrospinning technology to load TGF-β3, CTGF and bone marrow-derived MSCs onto polydopamine nanoparticles and polycaprolactone scaffolds, respectively, mimicking the structure of AF and achieving mechanical properties similar to those of natural AF in the rodents. Here, TGFB3 is linked to atrial fibrillation.