Researchers at the University of Oxford have developed a groundbreaking technique for 3D printing human stem cells to create an engineered tissue that mimics the structure of the cerebral cortex. How they did it: Using human induced pluripotent stem cells (hiPSCs) — which have the potential to generate most human cell types — the researchers fabricated a two-layered brain tissue. When implanted into mouse brain slices, these 3D-printed tissues managed to demonstrate structural and functional integration.