A 3D printing technique developed by researchers at Edinburgh’s Heriot-Watt University is producing clusters of human embryonic stem cells (hESCs) for the first time. The team believes that the breakthrough could lead to animal-free drug testing, and provide the foundation for custom replacement organs built from a patient’s own genetic code —potentially eliminating the risk of transplant rejection and the need for organ donation.

Until now, hESC cultures have been too delicate to print with

People have already used 3D printing techniques with hardier human cells like bone marrow and skin, as well as the embryonic stem cells of mice, but until now hESC cultures have been too delicate to print with. In partnership with Roslin Cellab, the university’s biomedical engineering group came up with a valve-based printing technique that produces highly-viable, uniformly-sized droplets of stem cells. Most importantly, though, the cells maintain their pluripotency — the ability to differentiate into every adult human cell type. While the prospect of lab-grown custom organs is incredibly exciting, the group is careful to temper its outlook, noting that any such application would be "in the longer term."