Researchers from Carnegie Mellon University used soft and living materials to create a biological scaffold, making a step closer to being able to 3D print a full-sized, adult human heart.

The study published on August 1 in the journal Science reported the first-of-its-kind technique that could print tissue scaffolds out of a major structural protein in the human body, the Xinhua news agency reported on August 1. Human organs like the heart are built from specialised cells that are held together by a scaffold called the extracellular matrix (ECM). It has not been possible until now to rebuild the complex ECM using traditional methods.

The technique called FRESH can print pieces of the heart out of collagen and cells into truly functional parts like a heart valve or a small beating ventricle, according to the study. The collagen is a desirable 3D-printing biomaterial since it makes up literally every single tissue in human body. But it starts out as a fluid and tends to deform during printing.

The FRESH technique allows collagen to be deposited layer-by-layer within a support bath of gel, so that the collagen could solidify in place before being removed from the gel. Then, the support gel would be melted away by heating from room temperature to body temperature without damaging the printed structure.

The FRESH is a robust and adaptable tissue engineering platform since a wide range of other soft gels including fibrin, alginate, and hyaluronic acid can be used. Also, the researchers managed to accurately reproduce patient-specific anatomical structure. Looking forward, it has potential applications in many aspects of regenerative medicine, from wound repair to organ bioengineering, according to the researchers.