In summary, we have found that in response to the stiffness variation of PECUU scaffolds, tBMSCs, i.e. the pre-differentiated BMSCs under TGF-β3 mediation, showed expression profiles of ECM genes (collagen-I, collagen-II and aggrecan) similar to the AF cells at different regions of native AF tissue. This evidence concerns the gene TGFB3 and atrial fibrillation.