摘要Although human-induced pluripotent stem cell-derived cardiomyocytes(hiPSC-CMs)have been used for disease modeling and drug discovery,clinically relevant three-dimensional(3D)functional myocardial micro tissues are lacking.Here,we developed a novel ring-shaped cardiac microtissue comprised of chamber-specific tissues to achieve a geometrically non-orientable ventricular myocardial band,similar to a Mobius loop.The ring-shaped cardiac tissue was constructed of hiPSC-CMs and human cardiac fibroblasts(hCFs)through a facile cellular self-assembly approach.It exhibited basic anatomical structure,positive cardiac troponin T(cTnT)immunostaining,regular calcium transients,and cardiac-like mechanical strength.The cardiac rings can be self-assembled and scaled up into various sizes with outstanding stability,suggesting their potential for precise therapy,pathophysiological investigation,and large-scale drug screening.