In Biophysics Reviews, researchers explore how human tissue models can be used to examine the impact of heart attacks and treatment of the fibrotic tissue outside the body, improving treatment and diagnosis. They use organoids, 3D organlike multicellular models derived from stem cells, to mimic natural development, structural organization, regeneration, and disease progression. Meanwhile, microfluidic devices control cell placement and fluid flow to act like the heart on a chip, while bioprinting allows cardiac tissue to be built up layer by layer.