A team at Carnegie Mellon University has created a full-sized 3D-bioprinted human heart model using the Freeform Reversible Embedding of Suspended Hydrogels (FRESH) technique. The model, created from MRI data using a specially built 3D printer, realistically mimics the elasticity of cardiac tissue and sutures.
The FRESH technique of 3D bioprinting was invented to fill a demand for 3D-printed soft polymers, which lack the rigidity to stand unsupported as in a normal print. FRESH 3D printing uses a needle to inject bioink into a bath of soft hydrogel, which supports the object as it prints. Once finished, a simple application of heat causes the hydrogel to melt away, leaving only the 3D-bioprinted object.
The major obstacle to achieving this milestone was printing a human heart at full scale. This necessitated the build ing of a new 3D printer custom-made to hold a gel support bath large enough to print at the desired size as well as minor software changes to maintain the speed and fidelity of the print.
Major hospitals often have facilities for 3D printing models of a patient's body to help surgeons educate patients and plan for the actual procedure; however, these tissues and organs can only be modeled in hard plastic or rubber. The team's heart is made from a soft, natural polymer called alginate, giving it properties similar to real cardiac tissue. For surgeons, this enables the creation of models that can cut, suture, and be manipulated in ways similar to a real heart. The immediate goal is to begin working with surgeons and clinicians to fine tune their technique and ensure it's ready for the hospital setting.
Surgeons can manipulate the model and have it actually respond like real tissue, so that when they get into the operating site, they've got an additional layer of realistic practice in that setting.