Two dimensional cell cultures have provided many insights regarding cardiac disease. However, 3D tissue models are superior due to their ability to aggregate and form cell-matrix interactions similarly to in vivo tissues [1-4]. For this project we aim to (1) bioengineer cardiac microtissues from human-iPSCs (hiPSCs), (2) direct differentiation of independent cell populations (e.g. cardiomyocytes, epithelial cells, fibroblasts, and endothethial cells), (3) merge these cell populations into heterogeneous microtissues, and (4) examine their collective ability to promote cardiac tissue maturation. Even though these components of bioengineering cardiac tissues are currently being redefined and have shown success [1-5]; we want to improve the quality of bioengineered cardiac tissues. To do this we will optimize the microenvironment in our 3D cell cultures with the aim to enhance maturation of cardiomyocytes.